Move team related functions to service layer (#32537)

There are still some functions under `models` after last big refactor
about `models`. This change will move all team related functions to
service layer with no code change.

services/user/user.go

@@ -188,7 +188,7 @@ func DeleteUser(ctx context.Context, u *user_model.User, purge bool) error {
 				break
 			}
 			for _, org := range orgs {
-				if err := models.RemoveOrgUser(ctx, org, u); err != nil {
+				if err := org_service.RemoveOrgUser(ctx, org, u); err != nil {
 					if organization.IsErrLastOrgOwner(err) {
 						err = org_service.DeleteOrganization(ctx, org, true)
 						if err != nil {