Migration to ReadTheDocs

[JonathanWenger]

This PR migrates the documentation from being built by Travis and being deployed to the gh-pages branch to being built and hosted by ReadTheDocs. This has the primary advantage that different versions of the documentation for different branches can be easily built and viewed in parallel.

Note: This changes the domain of the documentation from https://probabilistic-numerics.github.io/probnum/ to https://probnum.readthedocs.io

Todos:

• merge PR into development
• merge development into master
• Update settings in readthedocs dashboard
• Update repository website to probnum.readthedocs.io
• Update repository settings to not serve the gh-pages branch
• Delete gh-pages branch
• remove travis's github token

[JonathanWenger]

This closes #84 and #7 .

[JonathanWenger]

You can view the documentation generated by this PR at https://probnum.readthedocs.io. As soon as the PR is merged I will swap the underlying repo at ReadTheDocs to probabilistic-numerics/probnum from JonathanWenger/probnum.

[JonathanWenger]

Note: Docs for master will not build at probnum.readthedocs.io until changes from this PR are merged into master.

[nathanaelbosch]

Good job overall! I just added a few comments, but none of which is really crucial to fix. Probably the main point is the choice of how to properly name the two versions (default/development, master/development, stable/latest, or anything else).

[nathanaelbosch]

I also wondered: In this PR you ported the documentation in its current style to readthedocs. Does this only represent a migration to another domain (with additional functionality regarding multiple documentations of course!), or does this also include a statement/decision about the stylistic choice for the ProbNum documentation, i.e. "our current layout" vs "the common readthedocs layout"?

[JonathanWenger]

I also wondered: In this PR you ported the documentation in its current style to readthedocs. Does this only represent a migration to another domain (with additional functionality regarding multiple documentations of course!), or does this also include a statement/decision about the stylistic choice for the ProbNum documentation, i.e. "our current layout" vs "the common readthedocs layout"?

In order to reach a decision I ported our thematic choices of the docs to the readthedocs template. See here: https://probnum.readthedocs.io/en/docs-style/index.html
We might want a third opinion (e.g. @pnkraemer) here on what is better. Note that the documentation structure in the readthedocs template is still subject to change (in particular the structure could be more coherent).

[nathanaelbosch]

Awesome work Jonathan! I'm really impressed by seeing the documentation in both styles.

Personally, I think I slightly prefer the readthedocs layout, but I find it really hard to decide between both. But it really is awesome that we can compare both side by side :)

[nathanaelbosch]

Looks good to me!

[JonathanWenger]

Update:
The following larger changes are made by this commit:

• The documentation will from now on be hosted by ReadTheDocs at https://probnum.readthedocs.org
• The documentation can be viewed for different branches and releases
• The documentation style now is based off of sphinx_rtd_theme instead of bootstrap

During this migration I also changed much of the structure of the documentation and added some new sections to the documentation. During review I am mostly interested in feedback on the following:

General:

• Menu structure
• Intuitiveness of page (organization, page names, is information easy to find?)

Added Pages:

• Index Page
• Introduction
  • Probabilistic Numerics
  • ProbNum Quickstart

[nathanaelbosch]

My feedback, as discussed:

• use api names for the api documentation: "probnum.diffeq" instead of "Differential Equations", "probnum.utils" instead of "Other", etc
• different tutorial structure:
  • Remove "Case Studies" and "Advanced" since they are empty
  • Maybe use that level of structure (where "Advanced" was) to structure into diffeq, linalg, etc