Ported monster tank madness to lua

It would be nice, if someone could already have a look at this (style nits?),
although this is not completely finished yet (see [todo](https://github.com/abcdefg30/OpenRA/commit/e14ca26efa88f43f7da30762e2bc96975a6fc2d3#diff-da0b70bbc22b6b4af2fbe96dd5c5a8b7R15)).

[This](https://github.com/abcdefg30/OpenRA/commit/e14ca26efa88f43f7da30762e2bc96975a6fc2d3#diff-da0b70bbc22b6b4af2fbe96dd5c5a8b7R18) set to true can help testing.
Maybe AlliedForcesApproaching (aapro1.aud) or AlliedReinforcementsHaveArrived (aarrive1.aud) for announcer voices. Can also be an uplifting sound effect like bleep9.aud (similar but not identical to radar up).