[chore] Refactor account deleting/block logic, tidy up some other processing things (#1599)

* start refactoring account deletion

* update to use state.DB

* further messing about

* some more tidying up

* more tidying, cleaning, nice-making

* further adventures in refactoring and the woes of technical debt

* update fr accept/reject

* poking + prodding

* fix up deleting

* create fave uri

* don't log using requestingAccount.ID because it might be nil

* move getBookmarks function

* use exists query to check for status bookmark

* use deletenotifications func

* fiddle

* delete follow request notif

* split up some db functions

* Fix possible nil pointer panic

* fix more possible nil pointers

* fix license headers

* warn when follow missing (target) account

* return wrapped err when bookmark/fave models can't be retrieved

* simplify self account delete

* warn log likely race condition

* de-sillify status delete loop

* move error check due north

* warn when unfollowSideEffects has no target account

* warn when no boost account is found

* warn + dump follow when no account

* more warnings

* warn on fave account not set

* move for loop inside anonymous function

* fix funky logic

* don't remove mutual account items on block;
do make sure unfollow occurs in both directions!

internal/processing/account/account_test.go

@@ -91,8 +91,10 @@ func (suite *AccountStandardTestSuite) SetupTest() {
 	suite.oauthServer = testrig.NewTestOauthServer(suite.db)
 
 	suite.fromClientAPIChan = make(chan messages.FromClientAPI, 100)
-	suite.state.Workers.EnqueueClientAPI = func(ctx context.Context, msg messages.FromClientAPI) {
-		suite.fromClientAPIChan <- msg
+	suite.state.Workers.EnqueueClientAPI = func(ctx context.Context, msgs ...messages.FromClientAPI) {
+		for _, msg := range msgs {
+			suite.fromClientAPIChan <- msg
+		}
 	}
 
 	suite.transportController = testrig.NewTestTransportController(&suite.state, testrig.NewMockHTTPClient(nil, "../../../testrig/media"))