mail/mboxgrep: update to 0.7.10

[fuz]

Summary

mail/mboxgrep: update to 0.7.10

 - switch to upstream's new hoster
 - remove lots of old hacks and patches
 - remove hacked in OpenSSL dependency
 - patch makefiles to enable staging
 - adopt this unmaintained port

Changelog: https://git.datatipp.se/dspiljar/mboxgrep/releases/tag/0.7.10

Approved by:	... (mentor)

Test Plan

Tested with Poudriere on i386 amd64 FreeBSD 12.4 13.1.
Arm64 test results pending. See http://fuz.su/~fuz/freebsd/batch5

[flo]

Approved