* Add overview of active sessions

* Better display of browser/platform name

* Improve how browser information is stored and displayed for sessions overview

* Fix test

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

Avatars now have consistent styling across all pages; border radius can be adjusted with a SASS variable ($ui-avatar-border-size)

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.