Arma 3: add server branch option (#308)

* Add Arma 3

* Fix autoInit flag

* Add parameter file ability

* Update regex

* Remote netlog flag

* Add headless client settings

* Update mod settings

* Final changes

* Update arma3config.json

* Mod handling and other tweaks

* Remove unnecessary stages

* IP Binding setting changes

* Update arma3.kvp

* Update arma3.kvp

* Update arma3.kvp

* Final changes

* Arma: add branch option

arma3updates.json

@@ -4,7 +4,8 @@
         "UpdateSourcePlatform":"All",
         "UpdateSource":"SteamCMD",
         "UpdateSourceData":"233780",
-        "UpdateSourceArgs":"107410"
+        "UpdateSourceArgs":"107410",
+        "UpdateSourceVersion":"{{ServerBranch}}"
     },
     {
         "UpdateStageName":"Server Config Template Download",