[feature] Process outgoing Move from clientAPI (#2750)

* prevent moved accounts from taking create-type actions

* update move logic

* federate move out

* indicate on web profile when an account has moved

* [docs] Add migration docs section

* lock while checking + setting move state

* use redirectFollowers func for clientAPI as well

* comment typo

* linter? i barely know 'er!

* Update internal/uris/uri.go

Co-authored-by: Daenney <daenney@users.noreply.github.com>

* add a couple tests for move

* fix little mistake exposed by tests (thanks tests)

* ensure Move marked as successful

* attach shared util funcs to struct

* lock whole account when doing move

* move moving check to after error check

* replace repeated text with error func

* linterrrrrr!!!!

* catch self follow case

---------

Co-authored-by: Daenney <daenney@users.noreply.github.com>

internal/api/util/errorhandling.go

@@ -184,3 +184,21 @@ func OAuthErrorHandler(c *gin.Context, errWithCode gtserror.WithCode) {
 		"error_description": errWithCode.Safe(),
 	})
 }
+
+// NotFoundAfterMove returns code 404 to the caller and writes a helpful error message.
+// Specifically used for accounts trying to access endpoints they cannot use while moving.
+func NotFoundAfterMove(c *gin.Context) {
+	const errMsg = "your account has Moved or is currently Moving; you cannot use this endpoint"
+	JSON(c, http.StatusForbidden, map[string]string{
+		"error": errMsg,
+	})
+}
+
+// ForbiddenAfterMove returns code 403 to the caller and writes a helpful error message.
+// Specifically used for accounts trying to take actions on endpoints they cannot do while moving.
+func ForbiddenAfterMove(c *gin.Context) {
+	const errMsg = "your account has Moved or is currently Moving; you cannot take create or update type actions"
+	JSON(c, http.StatusForbidden, map[string]string{
+		"error": errMsg,
+	})
+}