Update gnupg to 2.2.1, and remove the security/gnupg22 port

I misjudged the timeline for 2.3, and had not processed that the
intent of 2.3 is different from 2.1. Rather than 2.3 being a "modern"
branch and 2.2 being purely "stable," 2.3 will be development and
users are encouraged to remain on 2.2. Furthermore, upstream doesn't
expent a 2.3 release for a year or so.

Accordingly, I'm removing the gnupg22 port and updating security/gnupg
to be 2.2. gnugp20 is still scheduled for deletion at the end of the
year.