(etke.cc-exclusive) Server Actions page (#457)

* WIP: add scheduler commands

* refactor scheduler commands page

* WIP on CRUD for ScheduledCommands

* more refactoring, finish CRUD On scheduled pages

* Add info text about Scheduler service

* Finish recurring commands add/edit

* add more texts

* fix server status behavior on not-loaded-yet state; adjust texts; lint fixes

* add link to the help pages in the commands palette

* Move Commands Panel to ServerSchedulesPage

* Rename Server Schedules to Server Actions

* more texts, a bit changed visual of the actions page, lint fix

* add docs

* fix tests

* Add UTC label to scheduled command create/edit

README.md

@@ -122,6 +122,7 @@ The following list contains such features - they are only available for [etke.cc
 * 📊 [Server Status indicator and page](https://github.com/etkecc/synapse-admin/pull/182)
 * 📬 [Server Notifications indicator and page](https://github.com/etkecc/synapse-admin/pull/240)
 * 🛠️ [Server Commands panel](https://github.com/etkecc/synapse-admin/pull/365)
+* 🚀 [Server Actions page](https://github.com/etkecc/synapse-admin/pull/457)
 
 ### Development