Allow phone number up to 13 digits. Add "Germany" to the country list.

[Kaffeine]

Hello and thank you for the fixes :+1: .

I have some small nitpicks :wink::

• Please follow the commit message format from The Seven Rules:
  • Limit the subject line to 50 characters (hard limit is 72)
  • Do not end the subject with a dot.
• Please adjust the custom phone length to 15 (as it is in the regexp)
• Please (naturally) split the commit into two:
  • Allow custom phone number up to .. digits
  • Add Germany to the country list.

[Kaffeine]

Merged! Thank you again :+1: