refs #22148 [fid_adlr] vf6 changelog

* remove static factories for record drivers, see also 21615
* additional: remove factory entries in module.config for not explicit overridden record drivers
* feedback form url error
** create policy back url by using route
** not vf6-upgrade specific

* add UBL internal docker mailer for ALPHA configuration
** easier testing
** all vufind mails will be send and redirect to itself (docker.ub.intern.uni-leipzig.de)