Tracking Beam weaponry

@IrateRedKite said they want to work on this with me, so now they will have to suffer my ineptitude. :)

The idea is to create a projectile or combination of projectiles that mimic as closely as possible a continuous beam weapon, whose sole purpose is definitely not just to imitate the boss fight against Pixy and his laser-armed fighter.

We *might* get away with a very glowy, super high velocity, super low lifetime projectile with almost no damage but absurd refire. It really depends on whether MP handles very high refire rates even worse than SP. Otherwise, we might need to do some trickery, and orient ourselves on that one Why485 video.

Start with the beam-projectile concept described in the issue, including the proposed high-velocity, low-lifetime projectile and the concerns about multiplayer versus single-player refire rates. Review the referenced Why485 video for the alternative approach. Done means implementing a projectile or projectile combination that closely mimics a continuous beam weapon.

Written by the indexing model from the issue text.