Fixes#2220
This drops the ability to shift+click on “Back” to get back to a pinned
column, but that was inconsistent, broken, and undocumented.
This also brings us slightly closer to upstream.
* Run eslint --fix
* Fix linting issues in video player and reduce divergences with upstream
This includes a behavior change of not auto-looping videos anymore. I don't
remember loops being ever intended, and they have been removed from upstream
a while ago, but we somehow missed the change.
* Fix lint issues in `app/javascript/flavours/glitch/selectors/index.js`
Those were basically caused by dead code that isn't present upstream, so
that brings us closer to upstream as well.
* Fix linting issue and bug in streaming/index.js
* Fix linting issues in config/webpack/shared.js
* Fix unused import in flavours/glitch/features/ui/index.js
* Fix linting issues and reduce divergences from upstream in flavours/glitch/features/ui/components/video_modal.jsx
* Fix linting issues in flavours/glitch/reducers
* Fix linting issues in glitch-soc onboarding modal
* Fix linting issues in flavours/glitch/features/ui/components/navigation_panel.jsx
* Remove dead code for unused local setting navbar_under
* Fix various linting issues
* Fix linting issues in flavours/glitch/components/scrollable_list.jsx and reduce divergences with upstream
