mail/cyrus-imapd310: fix 'pkg -r' install and simplify Makefile

[siva]

mail/cyrus-imapd310/Makefile

28

Now depending on pcre2 unconditionally since devel/pcre is deprecated and v3.10 prefers PCRE2 now based on https://www.cyrusimap.org/3.10/imap/download/upgrade.html#upgrade-pcre2-support

66

The once experimental backup support is now deprecated as of v3.10 https://www.cyrusimap.org/3.10/imap/download/upgrade.html#cyrus-backups-feature-is-deprecated-as-of-3-10

159

The following changes are made in this patch:

• Now using the standard FreeBSD ports framework way of specifying a user and group to create from the UIDs and GIDs list, since the cyrus user home is unimportant.
• /etc/services already contains an entry for port 4190 managesieve protocol, so no need to send a message to add it

pkg-install and pkg-deinstall scripts are now unnecessary, and were previously breaking a 'pkg -r' based installation.