Enable rebel AI to use rifle+muzzle combo grenade launchers

[jaj22]

What type of PR is this.

1. Bug
2. Change
3. Enhancement

What have you changed and why?

Rebel AI can't use the SPE grenade launcher rifles because they're broken down into base weapons when adding them to the arsenal. This PR searches categoryOverrides for suitable weapons and adds them in generateRebelGear when you have sufficient rifles and muzzles.

Probably a bit too dangerous for 3.3.3 because it has a small risk of causing issues in other modsets.

Please specify which Issue this PR Resolves.

closes #2897

Please verify the following and ensure all checks are completed.

1. Have you loaded the mission in LAN host?
2. Have you loaded the mission on a dedicated server?

Is further testing or are further changes required?

1. No
2. Yes (Please provide further detail below.)

Check if it does anything weird in other modsets.

How can the changes be tested?

After startup you can check the value of A3A_specialGrenadeLaunchers for weird shit. It's a hashmap with GL rifle classes as keys and [baseweapon, muzzle] values.

[MeltedPixel]

Looks Good.
Tests: Good.