Show avaliable fire support on scoreboard for each team

[LordDz]

Adds "Fire Support: " to the scoreboard, to make it easier for both the team and squad leaders to see how much fire support is left for the team to use.

Just another small commit to make the game easier to play and requiring less questions in the chat like "How much arty do we have left?" :)

Can split it into Artillery and Airstrikes when we get support for more than artillery, but for now I think this is enough.