gundam: Add beam rifle and vulcan shoot sounds to ReZEL

Probably we need copyright notice.
gundam: Initial model for Zeta Gundam
gundam: Adding body model to Zeta
gundam: Add arms and legs to Zeta
gundam: Add Waverider part to Zeta
gundam: Rescale Zeta to match ReZEL's size
gundam: Move ReZEL-draw.cpp into draw folder
gundam: Move StaticBind class definition to dedicated header

We'd probably move it to main executable project, because it could be
used by other modules as well
gundam: Add ZetaGundam class to gundam module

The sources and initialization scripts are copied from
ReZEL.
gundam: Move EntityCommands in ReZEL.h to a dedicated header
gundam: Add walk motion to ZetaGundam
gundam: Add aim motion to ZetaGundam
gundam: Add rifle and head vulcan muzzle position to ZetaGundam
gundam: Add medium leg bone and stand motion to ZetaGundam