Chore: Add user service method GetByLogin (#53204)

* Add wrapper around sqlstore method GetUserByLogin

* Use new method from user service

* Fix lint

* Fix lint 2

* fix middleware basic auth test

* Fix grafana login returning a user by login

* Remove GetUserByLogin from store interface

* Merge commit

pkg/services/user/model.go

@@ -58,6 +58,10 @@ type CreateUserCommand struct {
 	IsServiceAccount bool
 }
 
+type GetUserByLoginQuery struct {
+	LoginOrEmail string
+}
+
 func (u *User) NameOrFallback() string {
 	if u.Name != "" {
 		return u.Name