Clarify permission "HasAccess" behavior (#30585)

Follow #30495

"HasAccess" behavior wasn't clear, to make it clear:

* Use a new name `HasAnyUnitAccess`, it will be easier to review related
code and permission problems.
* Separate everyone access mode to a separate field, then all calls to
HasAccess are reverted to old behavior before #30495.
* Add new tests.

---------

Co-authored-by: Giteabot <teabot@gitea.io>

services/repository/transfer.go

@@ -387,7 +387,7 @@ func StartRepositoryTransfer(ctx context.Context, doer, newOwner *user_model.Use
 	}
 
 	// In case the new owner would not have sufficient access to the repo, give access rights for read
-	hasAccess, err := access_model.HasAccess(ctx, newOwner.ID, repo)
+	hasAccess, err := access_model.HasAnyUnitAccess(ctx, newOwner.ID, repo)
 	if err != nil {
 		return err
 	}