Fixes #875

Port SCSS changes from 3c033c4352 to glitch-soc

Port bb62827c16 to glitch-soc

Port 8389b496ba to glitch flavour

The modal-handling code gives back focus to the element focused when the
modal opened. However, in the case of reply confirmation, it would do so
*after* the composer code itself requested focus.

Port bfec030a4e to glitch-soc

Port 4fdefffb99 to glitch-soc

Port 4c03e05a4e to glitch-soc

This introduces new requirements in the API:

  `/api/v1/timelines/tag/:tag` now accepts new params: `any`, `all` and `none`
  It now returns status matching tag :tag or any of the :any, provided that
  they also include all tags in `all` and none of `none`.

Port relevant parts of 9d4541c612 to glitch-soc

WARNING: This may break some custom skins!

  `.drawer > .contents` has been moved to
  `.drawer > .drawer__pager > .drawer__iner`, and the waves have been moved
  from `.drawer > .contents` to `.drawer__inner__mastodon`!

Port 5bf100f87b to glitch-soc

Port 2e1b5edfea to glitch-soc

Port 4f42238c29 to glitch-soc

Port 90b64c0069 to glitch-soc

This is both for consistency with account timelines and to not mess with
the logic used to decide whether going back in the browser's history is
going to make us leave the WebUI.

Port 8182b61518 to glitch-soc

Port 4eeda67727 to glitch-soc

Port 06252ec71e to glitch-soc

Port 5ea643b279 to glitch-soc

Port 46061dc041 to glitch-soc

Port 7403e5d306 to glitch-soc

Port 12ab15e584 to glitch-soc

Port 13dce12665 to glitch-soc

Port SCSS changes from 087e118971 to glitch flavour

It should not be necessary thanks to our Content Security Policy, but best
be sure in case a server's CSP is incorrect. Also, avoids a CSP warning about
loading remote scripts.

* Make sure loading indicator has enough vertical space
* Respect reduce_motion setting for loading indicator

Port 4ede51743e to glitch-soc

Fixes #855

Port c58c00651b to glitch-soc

Port part of 7c48688d85 to glitch-soc

The `hasMore` property of timelines in redux store was set whenever an API
request returned only one page of results, *even* if the query only requested
newer statuses (using `since_id`), causing `hasMore` to be incorrectly set to
false whenever fetching new toots in a timeline, which happens each time
an account's timeline or media gallery is visited.

Display “load more” more consistently, add a loading indicator on first load.

(Even though that codepath is probably never actually used…)

Port ecd303c097 to glitch-soc

Port 73be8f38c1 to glitch-soc