Add PayPal Donate Function in Admin Area

[Clemens85]

SImilar to Wikipedia etc.

• [x] Add Button in Main-Nav (Desktop + Mobile) with Dialog about donation
• [x] Change Favicon to new logo
• [x] Add missing i18n
• [x] Add donation page inside PayPal
• [x] Check whether in own private account or a brand new account
• [x] Intercept team-message sending: Show own donation dialog after having sent emails (1-2 seconds deferred)
• [x] Store information that donation dialog was shown in localStorage and also if user wants to be reminded about it later
• [x] Show dialog also when sending dinner routes if user wanted to be reminded

[Clemens85]

Brainstorming:

• Always have somewhere a donate Button (maybe with some explanations)
• Show popup in Admin area after sending Mails (tbd)