Begin implementation of loadable hagar secondary. What this will do: When enabled...

Begin implementation of loadable hagar secondary. What this will do: When enabled, the user holds down the alt fire button to load rockets. The more it's held down, the more rockets are loaded into the hagar (one every X seconds). Once the button is released, the number of rockets that were loaded till that moment will be fired, in a pattern similar to the crylink primary. This will also be Xonotic's first "hold do load, the more the many" firing type.

Current code just causes hagar secondary to fire rockats in the same pattern as the crylink, which is just the first step.