Enable stances for helicopters in RA

Commit enables stance changes for helicopters in RA. It also sets default stance
to HoldFire to keep previous behaviour.

closes #7117
Add MustBeDestroyed to sniper and reorganize map.yaml
Merge pull request #7180 from abcdefg30/fix-lonestar

Repaired Fort Lonestar map
Cache GameServer joinable/compatible state across render frames.
Hide started games from the server list to reduce noise.
Show all mods in the server browser.
Merge pull request #7185 from zstyblik/pr20141224-heli-stances

Closes #7117
Disable SA1024 and SA1035.

These rules generate many false positives, and do not help with code readability within OpenRA.
Remove redundant StyleCop definitions.
Move OpenRA.Lint into a --check-yaml utility command.
Add --check-code-style utility command.
automatically check for code style violations
Don’t crash if a replay can’t be loaded.
Merge pull request #7190 from Mailaender/more-stylecop

Added yaml and code style analysis commands to OpenRA.Utility
Merge pull request #7187 from pchote/allmods

Show games from all compatible mods in the server browser.
Fix invalid spacing style warnings.
Info -> info.
Usings order.
Fix capitalization.
Fix variable ordering.