ports-mgmt/p5-FreeBSD-Portindex: deprecate and mark for removal before 2023Q2

This is something I wrote years ago, but haven't been actively
maintaining for some time. Recent changes to move the WWW setting
from pkg_descr to port Makefiles will certainly have broken
functionality, if it wasn't broken before. Also, it is dependent on
the deprecated db5 port through databases/p5-BerkeleyDB.

Since no one has complained, I guess no one is actually using this
software, so remove it from ports. If anyone wants to take this over,
contact me privately and I can pass the git repo to you.