Use Rails smart boolean cast to account for values such as "f",
"0", "false", etc. Previously, if a param was present in the request,
it would count as true.

* 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

* Move ApiController to Api/BaseController

* API controllers inherit from Api::BaseController

* Add coverage for various error cases in api/base controller