Code Formats, Nits & Unused Func/Var deletions (#15286)

* _ to unused func options

* rm useless brakets

* rm trifial non used models functions

* rm dead code

* rm dead global vars

* fix routers/api/v1/repo/issue.go

* dont overload import module

models/user.go

@@ -76,9 +76,6 @@ const (
 )
 
 var (
-	// ErrUserNotKeyOwner user does not own this key error
-	ErrUserNotKeyOwner = errors.New("User does not own this public key")
-
 	// ErrEmailNotExist e-mail does not exist error
 	ErrEmailNotExist = errors.New("E-mail does not exist")