Documentation Updates

[tpill90]

• Switch docs over to using variable replacement version of the documentation.
• Add python script to generate .svg screenshots from .ansi files, and update readme with new images. See : Adding script to generate an svg from .ansi files, and replacing all … steam-lancache-prefill#308
• Add copy button to MKdocs code snippets. See pull request Adding a copy button that will be displayed on code snippets in mkdocs steam-lancache-prefill#309
• Install section in readme should match SteamPrefill's install section.
• FAQ
  • Can I download games that I don't own?
• Write documentation for select-apps on detailed command usage page.
• Re-record cast on prefill's detailed command usage page. Has Steam specific output in it.

[tpill90]

In general, most of the documentation can/should be copy and pasted from SteamPrefill. Anything Steam specific should be removed.