Activating Plex hardware acceleration

@@@ INTEL GPU OFFLOAD NOTES @@@

If you have a supported Intel GPU, you can leverage hardware
accellerated encoding/decoding in Plex Media Server on FreeBSD 12.0+.

The requirements are as follows:

* Install multimedia/drm-kmod: e.g., pkg install drm-fbsd12.0-kmod

* Enable loading of kernel module on boot: sysrc kld_list+="drm"
** If Plex will run in a jail, you must load the module outside the jail!

* Load the kernel module now: kldload...