Minimize collected data (GDPR/DSGOV)

[sreichel]

For GDPR compliance we were told to reduce collected data ... https://www.it-recht-kanzlei.de/kontaktformular-datenschutzgrundverordnung-dsgvo.html#abschnitt_41

Contact form:

• name should not be required
• either phone or mail

Checkout:

• phone should be optional

Should this module cover GDRP - as far as possible?

[riconeitzel]

Will covered by #338 and #339