feat: convert demo front matter from TOML to YAML

Unfortunately, the popular Markdown editors (VS Code and Typora) still
don't support the more human-friendly TOML front matter syntax.

Therefore, make it easier to edit content in popular editors by
converting the demo front matter from TOML to YAML.

Except for publications as they are primarily data based (rather than
content based) and are automatically generated by Academic Admin.

Also, continue to use TOML for configuration files.

See #1069

exampleSite/content/authors/admin/_index.md

@@ -1,86 +1,74 @@
-+++
+---
 # Display name
-name = "Nelson Bighetti"
+name: Nelson Bighetti
 
 # Username (this should match the folder name)
-authors = ["admin"]
+authors:
+- admin
 
 # Is this the primary user of the site?
-superuser = true
+superuser: true
 
 # Role/position
-role = "Professor of Artificial Intelligence"
+role: Professor of Artificial Intelligence
 
 # Organizations/Affiliations
-#   Separate multiple entries with a comma, using the form: `[ {name="Org1", url=""}, {name="Org2", url=""} ]`.
-organizations = [ { name = "Stanford University", url = "" } ]
+organizations:
+- name: Stanford University
+  url: ""
 
 # Short bio (displayed in user profile at end of posts)
-bio = "My research interests include distributed robotics, mobile computing and programmable matter."
-
-# Enter email to display Gravatar (if Gravatar enabled in Config)
-email = ""
-
-# List (academic) interests or hobbies
-interests = [
-  "Artificial Intelligence",
-  "Computational Linguistics",
-  "Information Retrieval"
-]
-
-# Organizational groups that you belong to (for People widget)
-#   Set this to `[]` or comment out if you are not using People widget.
-user_groups = ["Researchers", "Visitors"]
-
-# List qualifications (such as academic degrees)
-[[education.courses]]
-  course = "PhD in Artificial Intelligence"
-  institution = "Stanford University"
-  year = 2012
-
-[[education.courses]]
-  course = "MEng in Artificial Intelligence"
-  institution = "Massachusetts Institute of Technology"
-  year = 2009
-
-[[education.courses]]
-  course = "BSc in Artificial Intelligence"
-  institution = "Massachusetts Institute of Technology"
-  year = 2008
+bio: My research interests include distributed robotics, mobile computing and programmable matter.
+
+interests:
+- Artificial Intelligence
+- Computational Linguistics
+- Information Retrieval
+
+education:
+  courses:
+  - course: PhD in Artificial Intelligence
+    institution: Stanford University
+    year: 2012
+  - course: MEng in Artificial Intelligence
+    institution: Massachusetts Institute of Technology
+    year: 2009
+  - course: BSc in Artificial Intelligence
+    institution: Massachusetts Institute of Technology
+    year: 2008
 
 # Social/Academic Networking
 # For available icons, see: https://sourcethemes.com/academic/docs/widgets/#icons
 #   For an email link, use "fas" icon pack, "envelope" icon, and a link in the
 #   form "mailto:your-email@example.com" or "#contact" for contact widget.
-
-[[social]]
-  icon = "envelope"
-  icon_pack = "fas"
-  link = "#contact"  # For a direct email link, use "mailto:test@example.org".
-
-[[social]]
-  icon = "twitter"
-  icon_pack = "fab"
-  link = "https://twitter.com/GeorgeCushen"
-
-[[social]]
-  icon = "google-scholar"
-  icon_pack = "ai"
-  link = "https://scholar.google.co.uk/citations?user=sIwtMXoAAAAJ"
-
-[[social]]
-  icon = "github"
-  icon_pack = "fab"
-  link = "https://github.com/gcushen"
-
+social:
+- icon: envelope
+  icon_pack: fas
+  link: '#contact'  # For a direct email link, use "mailto:test@example.org".
+- icon: twitter
+  icon_pack: fab
+  link: https://twitter.com/GeorgeCushen
+- icon: google-scholar
+  icon_pack: ai
+  link: https://scholar.google.co.uk/citations?user=sIwtMXoAAAAJ
+- icon: github
+  icon_pack: fab
+  link: https://github.com/gcushen
 # Link to a PDF of your resume/CV from the About widget.
-# To enable, copy your resume/CV to `static/files/cv.pdf` and uncomment the lines below.
-# [[social]]
-#   icon = "cv"
-#   icon_pack = "ai"
-#   link = "files/cv.pdf"
+# To enable, copy your resume/CV to `static/files/cv.pdf` and uncomment the lines below.  
+# - icon: cv
+#   icon_pack: ai
+#   link: files/cv.pdf
 
-+++
+# Enter email to display Gravatar (if Gravatar enabled in Config)
+email: ""
+
+# Organizational groups that you belong to (for People widget)
+#   Set this to `[]` or comment out if you are not using People widget.  
+user_groups:
+- Researchers
+- Visitors
+---
 
 Nelson Bighetti is a professor of artificial intelligence at the Stanford AI Lab. His research interests include distributed robotics, mobile computing and programmable matter. He leads the Robotic Neurobiology group, which develops self-reconfiguring robots, systems of self-organizing robots, and mobile sensor networks.
 

exampleSite/content/courses/_index.md

@@ -1,8 +1,9 @@
-+++
-title = "Courses"
+---
+title: Courses
+
+# Optional header image (relative to `static/img/` folder).
+header:
+  caption: ""
+  image: ""
+---
 
-# Optional featured image (relative to `static/img/` folder).
-[header]
-image = ""
-caption = ""
-+++

exampleSite/content/courses/example/_index.md

@@ -1,24 +1,25 @@
-+++
+---
 # Course title, summary, and position.
-linktitle = "An Example Course"
-summary = "Learn how to use Academic's docs layout for publishing online courses, software documentation, and tutorials."
-weight = 1  # Position of this course in course index. Comment out to order by date instead.
-
-# Page title
-title = "Overview"
-
-date = 2018-09-09T00:00:00  # Date published
-# lastmod = 2018-09-09T00:00:00  # Date modified
-
-draft = false  # Is this a draft? true/false
-toc = true  # Show table of contents? true/false
-type = "docs"  # Do not modify.
+linktitle: An Example Course
+summary: Learn how to use Academic's docs layout for publishing online courses, software documentation, and tutorials.
+weight: 1
+
+# Page metadata.
+title: Overview
+date: "2018-09-09T00:00:00Z"
+lastmod: "2018-09-09T00:00:00Z"
+draft: false  # Is this a draft? true/false
+toc: true  # Show table of contents? true/false
+type: docs  # Do not modify.
 
 # Add menu entry to sidebar.
-[menu.example]
-  name = "Overview"  # Declare this menu item as a parent with ID `name`.
-  weight = 1  # Position of link in menu.
-+++
+# - name: Declare this menu item as a parent with ID `name`.
+# - weight: Position of link in menu.
+menu:
+  example:
+    name: Overview
+    weight: 1
+---
 
 ## Flexibility
 

exampleSite/content/courses/example/example1.md

@@ -1,22 +1,18 @@
-+++
-title = "Example Page 1"
-
-date = 2018-09-09T00:00:00  # Date published
-# lastmod = 2018-09-09T00:00:00  # Date modified
-
-draft = false  # Is this a draft? true/false
-toc = true  # Show table of contents? true/false
-type = "docs"  # Do not modify.
+---
+title: Example Page 1
+linktitle: Tips 1-2
+toc: true
+type: docs
+date: "2019-05-05T00:00:00+01:00"
+draft: false
+menu:
+  example:
+    parent: Example Topic
+    weight: 1
 
 # Prev/next pager order (if `docs_section_pager` enabled in `params.toml`)
-weight = 1
-
-# Add menu entry to sidebar.
-linktitle = "Tips 1-2"  # Menu text - remove to use page title instead.
-[menu.example]
-  parent = "Example Topic"  # ID of parent menu entry.
-  weight = 1  # Position of link in menu.
-+++
+weight: 1
+---
 
 In this tutorial, I'll share my top 10 tips for getting started with Academic:
 

exampleSite/content/courses/example/example2.md

@@ -1,22 +1,18 @@
-+++
-title = "Example Page 2"
-
-date = 2019-05-05T00:00:00  # Date published
-# lastmod = 2018-09-09T00:00:00  # Date modified
-
-draft = false  # Is this a draft? true/false
-toc = true  # Show table of contents? true/false
-type = "docs"  # Do not modify.
+---
+title: Example Page 2
+linktitle: Tips 3-4
+toc: true
+type: docs
+date: "2019-05-05T00:00:00+01:00"
+draft: false
+menu:
+  example:
+    parent: Example Topic
+    weight: 2
 
 # Prev/next pager order (if `docs_section_pager` enabled in `params.toml`)
-weight = 2
-
-# Add menu entry to sidebar.
-linktitle = "Tips 3-4"  # Menu text - remove to use page title instead.
-[menu.example]
-  parent = "Example Topic"  # ID of parent menu entry.
-  weight = 2  # Position of link in menu.
-+++
+weight: 2
+---
 
 Here are some more tips for getting started with Academic:
 

exampleSite/content/post/_index.md

@@ -1,14 +1,14 @@
-+++
-title = "Posts"
+---
+title: Posts
 
 # View.
 #   1 = List
 #   2 = Compact
 #   3 = Card
-view = 2
+view: 2
 
-# Optional featured image (relative to `static/img/` folder).
-[header]
-image = ""
-caption = ""
-+++
+# Optional header image (relative to `static/img/` folder).
+header:
+  caption: ""
+  image: ""
+---