Add scheduling module to sdk extensions

Add visibility of the sdkinfo proto, as well as an enum for the module
to be used by SdkExtensions.

Bug: 188787081
Test: m com.android.scheduling and inspect it
Change-Id: I5727e361b79ab0860d692261bde5f0b54279f791

proto/sdk.proto

@@ -36,6 +36,7 @@ enum SdkModule {
 
   // S modules
   ART = 8;
+  SCHEDULING = 9;
 }
 
 // A single extension version.

tools/Android.bp

@@ -63,6 +63,7 @@ prebuilt_etc {
         "//packages/modules/Connectivity:__subpackages__",
         "//packages/modules/IPsec/apex:__subpackages__",
         "//packages/modules/Permission:__subpackages__",
+        "//packages/modules/Scheduling:__subpackages__",
         "//packages/modules/SdkExtensions:__subpackages__",
         "//packages/modules/StatsD:__subpackages__",
         "//packages/providers/MediaProvider:__subpackages__",