cg_players: implement `trap_R_BatchInPVS` to test if a bunch of entities are in PVS in one call

[illwieckz]

Use trap_R_inPVSArray to test array of entities in PVS in one call.

Game sidecar of:

• https://github.com/DaemonEngine/Daemon/pull/852

[illwieckz]

I added a commit removing an useless vec3 copy and an useless function call:

Sometime I find things that are very meh:

Edit: On screenshot is an optimized build but without LTO, I guess LTO could optimize that, but really, that made no sense.

[illwieckz]

Las change just modified some comment/spacing and moved a comment to a separate commit (no functional change).

[slipher]

LGTM