Separate snapshot definition

Current snapshot definition is located in the CC module, so it is
difficult to capture non-CC module (such as prebuilt_etc) to the
snapshot. Separate general snapshot definition from cc so other modules
can also define its own snapshot.

Bug: 192430376
Test: m nothing passed
Change-Id: Ifb69fb3d2ec555b629aa31ec03e7ce5831fd3063

cc/snapshot_utils.go

@@ -114,7 +114,7 @@ func ShouldCollectHeadersForSnapshot(ctx android.ModuleContext, m LinkableInterf
 	}
 
 	for _, image := range []SnapshotImage{VendorSnapshotImageSingleton, recoverySnapshotImageSingleton} {
-		if isSnapshotAware(ctx.DeviceConfig(), m, image.isProprietaryPath(ctx.ModuleDir(), ctx.DeviceConfig()), apexInfo, image) {
+		if isSnapshotAware(ctx.DeviceConfig(), m, image.IsProprietaryPath(ctx.ModuleDir(), ctx.DeviceConfig()), apexInfo, image) {
 			return true
 		}
 	}