* add missing locales for French translation

* accent "Media" in the front-end locales

* images => médias

* Change 'rapport' to 'signalement' in French locales to be more coherent

* fix typo

* remove duplicate EN locale

* translate missing locales

* update missing locale

* fix typo

* unify with "utilisateur⋅ice⋅s"

* address PR comments

* Faster emojify() algorithm, avoid regex replace

* add semicolon

* feat(components/media_gallery): Responsive images

* fix(components/media_gallery): Link to image URL

* Remove unused column_collapsable.js
* Remove old styles
* Extract `> div`  style to independent class

ref https://tc39.github.io/proposal-decorators/

(This patch has been merged as bugfix and reverted, but still valuable as
improvement)

Previously, we've attached IntersectionObserver twice for boosted statuses:
wrapper Status and wrapped Status. but wrapped Status don't need to manage
intersection and visibility by itself, because it's a part of wrapper Status.

* Revert "Bump version to 1.4.4"

This reverts commit 1585b0c6cc.

* Revert "Fix conversations (fixes #3869) (#3870)"

This reverts commit 15b43f555d.

* Revert "Fix streaming server. Redis connection subscribe for each channel. (#3828)"

This reverts commit d8ec832806.

* Revert "Filter direct statuses in Status.as_home_timeline (#3842)"

This reverts commit bab5a18232.

* Revert "Fix RemoteFollow behavior (#3868)"

This reverts commit a20cf3b64e.

* Revert "Update fabricator for MediaAttachment to attach a file according to type (#3862)"

This reverts commit 356df7ae6b.

* Revert "Upgrade React Router (#3677)"

This reverts commit 8f03fdce7f.

* Revert "Do not call setState from unmounted component (#3853)"

This reverts commit 1fc6cb4997.

* Revert "Replace TextIconButton for SensitiveButton to IconButton (#3759)"

This reverts commit eb832e88f4.

* Revert "Fix RTL detection on Ruby side (#3867)"

This reverts commit b16b69350e.

* Revert "i18n: Fixed typo in Polish translation (#3864)"

This reverts commit da6fa029f6.

* Revert "Don't attach IntersectionObserver for wrapped statuses (#3863)"

This reverts commit 94ad0706f5.

* chore(yarn): Remove react-router

* chore(yarn): Remove react-router-scroll

* chore(yarn): Remove history

* chore(yarn): Add react-router-dom

* chore: Remove usages of react-router-scroll

* refactor: Upgrade to react-router-web

* refactor: Use fork of react-router-scroll

This reverts commit 2ddea9a6c8.

* fix: Issues mentions in the PR feedback

Stop an executing task if the component already unmounted.

* Replace TextIconButton for SensitiveButton to IconButton

* line-height

This fixes a bug that sometimes boosted statuses being hidden on scrolling.

Previously, we've attached IntersectionObserver twice for boosted statuses:
wrapper Status and wrapped Status. This will call intersection handler twice,
so this may results race condition...probably.

* Bring Toot button in line with counter

Both should use stringz I guess

* Use grapheme_length for character count

* Debounce autosuggestions

* Remove duplicate import

mergeDeep also merges columns, but it should be replaced simply.

So in the new function, first apply mergeDeep except columns, and set default columns if columns unset.

* i18n: minor fix in Polish translation

* i18n

* Unread indicator was invisible behind column header, adjusted

* Unread indicator now a CSS pseudo-element

* Adjust flex

* Update Russian translation (pin)

follow up #3564

* Re-add clear notifications button

* remove connect() in column_settings

* one line

* remove unused props

* Move ancestors/descendants out of timelines reducer

* Refactor timelines reducer

All types of timelines now have a flat structure and use the same
reducer functions and actions

* Reintroduce some missing behaviours

* Fix wrong import in reports

* Fix includes typo

* Fix issue related to "next" pagination in timelines and notifications

* Fix bug with timeline's initial state, expandNotifications