Separate email handling for group members

A common issue for team members is that they'd like to handle the approver/payer email separately to their own personal requests.

Currently the DPL has a personal account and a leader account to wear two hats.

Proposals for separating email:

1. Create an explicit notification email for each approver/payer team. This can be static in config. e.g. treasurer@spi, leader@debian, etc.
2. Allow users to configure emails per group that they're a part of.

1 is much simpler. Would it work for SPI (@tbm, @zumbi, @Perdu), Debian France (@peb), Debian.ch (@hug) and our Leader (@tille)?