cleanup: Remove expired ports:

devel/erlang-exmpp: last upstream patches over 10 years ago
sysutils/showbeastie: Broken on FreeBSD 12 and above since 2018
2021-09-30 www/squid3: Unsupported by upstream
2021-09-30 sysutils/cfengine310: OpenSSL 1.1.X is not supported.
2021-09-30 security/py-paramiko1: Out of date version. No consumer now. Use security/py-paramiko
2021-09-30 sysutils/cfengine-masterfiles310: cfengine310 will retire at FreeBSD 11 EOL
2021-09-30 security/openca-tools-forked: Use modern port security/libscep instead
2021-09-30 multimedia/sms1xxx-kmod: Supports DVB API v3 only. Use multimedia/webcamd instead
2021-09-30 sysutils/cfengine311: OpenSSL 1.1.X is not supported.
2021-09-30 sysutils/cfengine-masterfiles311: cfengine311 will retire at FreeBSD 11 EOL
2021-09-30 mail/postfix35: It is only here until FreeBSD 11 is EoL (Postfix >= 3.6 requires OpenSSL >= 1.1.x)