Port 28401962ca to glitch-soc

Port 185cb2dc3a to glitch-soc

Media modals push an history state so that pressing back on mobile closes them.
We made sure to not scroll when opening them, but not when *closing* them,
which caused some issues in rare cases.

Inspired by b79ab15859

Port f7a6f9489d to glitch-soc

[API] [vanilla required] [glitch-soc optional] initial_state show_sensitive_media boolean changed to show_media string with options "default", "hide_all", "show_all"

Port df2f4052b8 to glitch-soc

Port 9f6662fcc9 to glitch-soc

Port d0d65b5a28 to glitch-soc

Fixes #751

Port 05f90e3695 to glitch-soc

Port front-end changes from f4d549d300 to glitch-soc

Port some parts from 1a7a74ff76

Port front-end changes from f8b54d229f

Port SCSS changes from f4d549d300

Port SCSS changes from:
- a58ec29631
- cdfe51e325
- 1f6ed4f86a
- 617f40fc2b
- 6a0d4d36ad
- 2374a00c10
- a2cabf3f4a

Port SCSS from 011437dcb5 to glitch-soc

if spoiler-text doesn't already start with re:, we prepend `re: `
ourselves in replies.

This implements https://github.com/tootsuite/mastodon/issues/8667
Following Plemora's example: https://git.pleroma.social/pleroma/pleroma-fe/merge_requests/318

Port 7b7c26063e to glitch-soc

Port f66a786029 to glitch-soc