[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/db/bundb/bundb_test.go

@@ -44,6 +44,8 @@ type BunDBStandardTestSuite struct {
 	testFollows      map[string]*gtsmodel.Follow
 	testEmojis       map[string]*gtsmodel.Emoji
 	testReports      map[string]*gtsmodel.Report
+	testBookmarks    map[string]*gtsmodel.StatusBookmark
+	testFaves        map[string]*gtsmodel.StatusFave
 }
 
 func (suite *BunDBStandardTestSuite) SetupSuite() {
@@ -59,6 +61,8 @@ func (suite *BunDBStandardTestSuite) SetupSuite() {
 	suite.testFollows = testrig.NewTestFollows()
 	suite.testEmojis = testrig.NewTestEmojis()
 	suite.testReports = testrig.NewTestReports()
+	suite.testBookmarks = testrig.NewTestBookmarks()
+	suite.testFaves = testrig.NewTestFaves()
 }
 
 func (suite *BunDBStandardTestSuite) SetupTest() {