improve UX of GPG encrypted messages
Actual behavior: When receiving a GPG encrypted message, there is a big green banner at the top.
UX Problems:
- it takes a lot of valuable UI space
- the big green area is a bit offensive wrt to the rest of Evolution UI, which is always in the same neutral tone
- it's redundant with the field
Security: | GPG signed, GPG encrypted
which appears just below after the subject and date.
Proposal:
We merge this banner with the Security
header: