Place reactor_final.pk3 in /etmain dir

Scenario:
The Axis are nearing completion of the world's first functional nuclear reactor. Allies must destroy it at all costs.

The Allied strike team has devised an ingenious plan. Instead of striking at the heavily defended reactor, they will strike at the lightly defended coolant tanks, using stolen explosives and a hijacked truck to gain entry to the base.

Objectives (allied):

Phase I
1. Steal box of explosives and bring to truck
2. Steal truck
3. Use truck to ram main gate

Phase II
4. Blow up the coolant controls (rebuildable) which will start the coolant draining. Allies win when both tanks drain, thus causing the Axis experimental reactor to blow up