net-im/prosody: refactor and move to lua 5.2

• Use Lua 5.2 and drop support for the dead LuaJIT.
• Explicitly state all required configure options as the "freebsd" preset has some of them wrong.
• Do not install the example certs as they clutter the config directory and nobody should ever use them. They can be recreated with prosodyctl if needed.
• Remove the broken "daemonize" option from the rc script, handle all actions with "prosodyctl" instead.
• Change data directory from /usr/local/var/lib/prosody to /var/db/prosody and include instructions in UPDATING
• Install the prosody migrator
• Use arc4random

PR: 241619
Submitted by: thomas@beingboiled.info
Reviewed by: lx (maintainer), Sascha Biberhofer <ports@skyforge.at>
Approved by: lx (maintainer timeout)