Save initial signup information for users to aid in spam prevention (#31852)

This will allow instance admins to view signup pattern patterns for
public instances. It is modelled after discourse, mastodon, and
MediaWiki's approaches.

Note: This has privacy implications, but as the above-stated open-source
projects take this approach, especially MediaWiki, which I have no doubt
looked into this thoroughly, it is likely okay for us, too. However, I
would be appreciative of any feedback on how this could be improved.

---------

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

services/auth/source/ldap/source_sync.go

@@ -129,7 +129,7 @@ func (source *Source) Sync(ctx context.Context, updateExisting bool) error {
 				IsActive:     optional.Some(true),
 			}
 
-			err = user_model.CreateUser(ctx, usr, overwriteDefault)
+			err = user_model.CreateUser(ctx, usr, &user_model.Meta{}, overwriteDefault)
 			if err != nil {
 				log.Error("SyncExternalUsers[%s]: Error creating user %s: %v", source.authSource.Name, su.Username, err)
 			}