* Split "my library" into "video space (channels, videos...)" and "my library (playlists, history...)"
* Split "admin" into "overview (users, videos...)", "moderation (abuses, blocks, registrations...)" and "settings (configuration, runners...)"
* Reorganize the header and the left menu: account settings/notifications are now in the header
* Add instance information context in the left menu
* Merge dedicated videos pages for "recently added", "trending", "local videos" into a "browse videos" page that includes quick filters
* Clean up entire CSS
* Clean CSS variables so it's easier to theme PeerTube (some new variables fallback to old variables to limit currnet themes breakages)
* Replace the current light theme into a new one (beige)
* Add a dark (brown) theme (included in PeerTube core)
* Fix accessibility issues with old light theme colors (white on orange button for example)
* Redesign the left menu, the horizontal menu, form controls and buttons, "Discover videos" page and common video filters panel
* Replace/remove/add some global icon
