Add security/rubygem-openssl: Ruby gem that wraps around the OpenSSL library

[jrm]

Summary

Adding this because it is a new dependency of www/rubygem-ostatus2, which in
turn is a dependency of the upcoming net-im/mastodon port.

Test Plan

portlint -C: OK
testport: OK (poudriere: 10.3-RELEASE-p10, i386)
testport: OK (poudriere: 10.3-RELEASE-p10, amd64)
testport: OK (poudriere: 11.0-RELEASE-p1, i386)
testport: OK (poudriere: 11.0-RELEASE-p1, amd64)

[swills]

Looks fine and I guess we'll need it eventually, might as well make it available.