net/luasocket-53

USES=lua gained flavors.

Ports using USES=lua:module or lua:flavors will be flavored.  A range of
supported lua versions can be set using XX-YY (or XX-, or -YY, or simply ZZ)
for ports not supporting all lua versions.

USES=lua sets LUA_FLAVOR that needs to be used on all dependencies of
flavored lua ports, in a similar way as PHP or Python flavors.

PR:		245038
Submitted by:	andrew tao11 riddles org uk
Reviewed by:	mat, kevans, russ haley gmail com
Approved by:	mat (portmgr)
Differential Revision:	https://reviews.freebsd.org/D16494

- Remove explicit mention that IPv4 and IPv6 are supported,   this is assumed by default in 2020 - Ensure that both slave ports have correct COMMENT line

- Add luasocket-53 port, based on luasocket-51 port