* Add messages informing that collections are empty

Adds empty messages to blocked users, domain blocks, favourited statuses, users
that favourited toot, follow requests, followers of given user, user's being
followed by given user, lists, muted users, toots' boosts.

Switched from using ScrollContainer to ScrollableList and/or added empty
message's text.

Fixes #4115

* Update localization files with strings for #4115

* Fix whitespace issues pointed out by codeclimate

* Add list of lists component to web UI

* Add list adding

* Add list removing

* List editor modal

* Add API account search limited by following=true relation

* Rework list editor modal

* Remove mandatory pagination of GET /api/v1/lists/:id/accounts

* Adjust search input placeholder

* Fix rspec (#5890)

* i18n: (zh-CN) Add missing translations for #5811 (#5891)

* i18n: (zh-CN) yarn manage:translations -- zh-CN

* i18n: (zh-CN) Add missing translations for #5811

* Fix some issues

- Display loading/missing state for list timelines
- Order lists alphabetically in overview
- Fix async list editor reset
- Redirect to /lists after deleting unpinned list
- Redirect to / after pinning a list

* Remove dead list columns when a list is deleted or fetch returns 404