Fixes #780

Fixes #778

* Add conversations API

* Add web UI for conversations

* Add test for conversations API

* Add tests for ConversationAccount

* Improve web UI

* Rename ConversationAccount to AccountConversation

* Remove conversations on block and mute

* Change last_status_id to be a denormalization of status_ids

* Add optimistic locking

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.

Signed-off-by: Marcin Mikołajczak <me@m4sk.in>

* Change documentation URL

* Fix hardcoded documentation URL in locales

* RTL: fix margins of public-account-header__tabs

* fix style

* even more stylish code :)

* Add a confirmation dialog when hitting reply and the compose box isn't empty

Fixes #878

* Performance improvement

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

* RTL: fix margins: public-layout.header.nav-button

* add empty line to meet style guides

Fixes #751

Port 05f90e3695 to glitch-soc

* Revert "Fix some icon names changed by the Font Awesome 5. (#8796)"

This reverts commit 3f9ec3de82.

* Revert "Migrate to font-awesome 5.0. (#8799)"

This reverts commit 8bae14591b.

* Revert "Fix some icons names, unavailable in fontawesome5 (free license). (#8792)"

This reverts commit b9c727a945.

* Revert "Update the icon name changed by the Font Awesome 5. (#8776)"

This reverts commit 17af4d27da.

* Revert "Add bot icon to bot avatars and migrate to newer version of Font Awesome (#8484)"

This reverts commit 4b794e134d.

Fixes #8755

Show "read more" link on overly long in-stream statuses

- pencil => pencil-alt
- sliders => sliders-h

related: #8484 #8776