Activate card confirmation mail per region

[f1sh1918]

Is your feature request related to a problem? Please describe. As a region i may not want to make the card earlier usable and not send an activation mail.

Describe the solution you'd like

• add a section in the administration where region admins can activate/deactivate the card confirmation mail
• send only card confirmation mail if the its activated
• set the confirmationFeatureFlag true

[dkehne]

@f1sh1918 description text for the checkbox is approved and should be in German "Nach der Erstellung einer Karte verschickt das System eine E-Mail-Bestätigung an den Antragsstellenden mit einem Link zur Vorab-Aktivierung"