Merged requested to merge install_doc into develop
Made several changes on the doc, especially:
- restructuredd/refactored install docs
- Added missing pages to TOC when needed
- Minimal wording/layout/typos improvements
- Added new Uninstall docs
- Fixed #1345 (closed)
- Fixed all warnings in sphinx build process (restructuredText syntax errors, etc.)
- Updated certbot instructions to use snap instead of distro packages, as recommended per certbot themselves.
- Added favicon to docs
- Changed authorship of doc from "Eliot Berriot" to "The Funkwhale Collective"
- Committed changelog fragments