(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

src/synapse/authProvider.test.ts

@@ -87,6 +87,7 @@ describe("authProvider", () => {
       expect(fetch).toHaveBeenCalledWith("example.com/_matrix/client/v3/logout", {
         headers: new Headers({
           Accept: "application/json",
+          "Content-Type": "application/json",
           Authorization: "Bearer foo",
         }),
         method: "POST",