First pass at rebranding changes, including:
* Changes to remove 'swarm.' from Workshop URLS, so swarm.workshop -> workshop.
* Changed URL for Copyright.
* Renamed get_helix_binaries.sh -> get_p4_binaries.sh, with associated directory and doc changes.
* Accounted for rename of HAS -> P4AS.
* Changed HMS references to P4MS.
* Replaced "Helix" and "Helix Core" references.
* Renamed variables to reduce tech debt buildup induced by rebranding.
* Changed default mount points:
/hxdepots[-1,N] -> /p4depots[-1,N]
/hxmetadata[1,2] -> /p4db[-1,2]
/hxlogs -> /p4logs
Also made some changes related to rebranding going out with r25.1.