Added FirewallConfigManager; Changed ContextImpl and Context; Changed FirewallConfigManagerService to FirewallConfigService and placed it under android.os; Modified Android.mk files

Change-Id: I49cad48fa52a7a3be860163c413f4affdfa0dcf3
Added FirewallConfigManager; Changed ContextImpl and Context; Changed FirewallConfigManagerService to FirewallConfigService and placed it under android.os; Modified Android.mk files

Change-Id: Iae6ac3a5eb1414700a10eadae81c426b602b0762