Remove unstaged japanese/prime and 3 of its dependencies (2 unstaged)

The japanese/scim-prime port was actually staged but it requires
japanese/prime to run which is being removed, so scim-prime is being
removed as a cascade.
Remove unstaged graphics/povray31 and cascade remove graphics/pmvpov

The only reason for povray31 to exist is to support pmvpov.  Unfortunately
for the latter, the former wasn't staged.  Neither port is maintained.
security/hydra: Switch Firebird client options from 2.1 => 2.5

databases/firebird21-* will be removed imminently.  Hydra has a
non-default option that relies on the firebird client library which
the currently version of Firebird (2.5.x) also has.  This change
is untested.  There's no revbump because the option is not normally set.

Change is necessary, it's an attempt to avoid breakage when Firebird
ports are removed.
Removed unstaged database/firebird21-* ports

Also remove reference to them in bsd.database.mk
Rather than fetching the data files and piping them through gunzip,
download them completely and then gunzip them. This preserves the
modtimes, and is the only way of knowing the actual age of the
data files.

Suggested by:	ache