refs #16480 [fid_adlr] styling of contact form

* fix link to contact form
** delete link for development from header
** add link in footer
** style link as specified in mockup, use icon moon for arrow
** use / add translation
* fix text on home page - fit as mockup
* refactor preselect form
** lower font-size of headline / h1 => h2
** change translations for subject and submit button
* style and refactor second feedback forms
** configure default fields in FeedbackForms.yml to hard override defaults by same name (name / email)
** order inputs in second form (after preselect) by FeedbackForms.yml
** remove unused / duplicated code / add comments
** TODO: merge preselect.phtml into form.phtml and preselectAction into formAction
** set textarea min height in feedback forms by css
** set required attribute styling like in registration forms
* feedback forms:
** add config for alpha
** remove unused user in preselect action
** add necessary label for dummy elements in Feedback.yaml
** fix caching of email subject in form action
** fix privacy notice check
** change translations on main form and response text
** change recipient to adlr.link