chore: add basic doc gen

[boneskull]

This adds basic documentation generation via appium-docs.

Future work should include:

• Add the human-written docs to the nav in mkdocs.yml
• More descriptions of commands (in docstrings)
• Some sort of landing page or otherwise fix the broken links in the generated README.md
• Add a workflow to build and/or publish docs

To build & serve:

npm exec appium-docs build -- --serve

[boneskull]

Current dependencies on/for this PR:

• master
  • PR feat: add all the types #635
    • PR chore: adapt to use execute methods #636
      • PR chore: add basic doc gen #638 👈

This comment was auto-generated by Graphite.

[boneskull]

I'm unsure if we need to add ./node_modules/appium-android-driver to the entryPoints in typedoc.json. If we do need something there, we will need to add tsconfig.json to its files prop of package.json. Someone may want to take a look and see if there are any commands missing from the doc output that are only defined in appium-android-driver.

Note that appium-android-driver has no executeMethodMap and no such commands are inherited this way.