feat: Add splash screen, instructions, tech foundation (#8)

Because the learner should know that the app is loading and not frozen,
and easily find instructions when needed,
this commit will:
  - add inital splash screen on load in both browser and PWA
  - add splash animation inline in index.html awaiting App component
  - add barebones instructions overlay
  - add functional navigation bar
  - remove unnecessary scroll bar when NOT on mobile
  - update icons and splash graphics

For the benefit of developer efficiency, this commit will:
  - fix linting
  - use Vuetify.js for layout
  - update @vue/cli and plugins to latest
  - add amplify cfg to Vue.js project
  - move 'push to s3' script into packages.json scripts section
  - move dev wiki to separate repo
  - add yarn versioning and local yarn

Closes #1, #2, #6, #8

Signed-off-by: toshify <4579559+toshify@users.noreply.github.com>

README.md

@@ -2,7 +2,55 @@
 
 A mobile-first literacy webapp for adult Chinese.
 
-* [TODO](wiki/TODO.md)
-* [Infrastructure](wiki/infrastructure.md)
-* [Resources](wiki/resources.md)
-* [Setup](wiki/setup.md)
+## Development
+
+```sh
+# Install git
+sudo apt install git
+
+# Clone this git repo
+git clone git@github.com:toshify/shizi.git target-dir
+
+# Install [NVM](https://github.com/nvm-sh/nvm) to handle node versions (ensure v#.##.# is latest version):
+curl -o- https://raw.githubusercontent.com/nvm-sh/nvm/v0.35.3/install.sh | bash
+
+# Reload terminal
+exit
+Ctrl-Alt-T
+# or instead
+source ~/.bashrc
+
+# Then install latest Node LTS
+nvm install --lts
+
+# Install [yarn](https://yarnpkg.com/getting-started/install) globally
+npm install -g yarn
+
+# Navigate to repo
+cd shizi/vue # or target-dir/vue or target-dir/react
+
+# Install packages
+yarn # equivalent of: yarn install
+
+# Start the app in local demo
+yarn start
+```
+
+## Update tools
+
+### NVM
+Re-install [NVM](https://github.com/nvm-sh/nvm) to update (ensure v#.##.# is latest version):
+```sh
+curl -o- https://raw.githubusercontent.com/nvm-sh/nvm/v0.35.3/install.sh | bash
+```
+
+### Node
+```sh
+nvm install --lts
+```
+
+### Yarn
+```sh
+yarn set version latest
+```
+