Implement bp2build for the `package` module

* We are interested mostly in the conversion the `default_applicable_licenses`
  attribute, as `default_visibility` cannot be handled until every module's
  `visibility` is handled.
* Several referenced license modules had to be manually enabled for
  conversion, and likewise a few trivial Android.bp containing only
  package and license modules.
* As Bazel allows only a single `package` rule, the package rules in a
  manually converted BUILD.bazel files were removed (in
  external/protobuf and prebuilts/clang/host/linux-x86 trees).
* The converted package rule is emitted before the `load` statements per
  Bazel documentation.

Bug: 190817312
Test: treehugger
Change-Id: If8bf6fee1580177de3bb402923615bcd48923ed2
diff --git a/android/allowlists/allowlists.go b/android/allowlists/allowlists.go
index ab028e5..e55f297 100644
--- a/android/allowlists/allowlists.go
+++ b/android/allowlists/allowlists.go
@@ -37,6 +37,7 @@
 
 var (
 	Bp2buildDefaultConfig = Bp2BuildConfig{
+		"art":                                   Bp2BuildDefaultTrue,
 		"art/libartbase":                        Bp2BuildDefaultTrueRecursively,
 		"art/libartpalette":                     Bp2BuildDefaultTrueRecursively,
 		"art/libdexfile":                        Bp2BuildDefaultTrueRecursively,
@@ -54,6 +55,7 @@
 		"build/soong/cc/libbuildversion":     Bp2BuildDefaultTrue, // Skip tests subdir
 		"build/soong/cc/ndkstubgen":          Bp2BuildDefaultTrue,
 		"build/soong/cc/symbolfile":          Bp2BuildDefaultTrue,
+		"build/soong/licenses":               Bp2BuildDefaultTrue,
 		"build/soong/linkerconfig":           Bp2BuildDefaultTrueRecursively,
 		"build/soong/scripts":                Bp2BuildDefaultTrueRecursively,
 
@@ -98,6 +100,7 @@
 		"external/aac":                           Bp2BuildDefaultTrueRecursively,
 		"external/arm-optimized-routines":        Bp2BuildDefaultTrueRecursively,
 		"external/auto/android-annotation-stubs": Bp2BuildDefaultTrueRecursively,
+		"external/auto":                          Bp2BuildDefaultTrue,
 		"external/auto/common":                   Bp2BuildDefaultTrueRecursively,
 		"external/auto/service":                  Bp2BuildDefaultTrueRecursively,
 		"external/boringssl":                     Bp2BuildDefaultTrueRecursively,
@@ -232,6 +235,7 @@
 		"prebuilts/runtime/mainline/platform/sdk":  Bp2BuildDefaultTrueRecursively,
 		"prebuilts/sdk/current/extras/app-toolkit": Bp2BuildDefaultTrue,
 		"prebuilts/sdk/current/support":            Bp2BuildDefaultTrue,
+		"prebuilts/tools":                          Bp2BuildDefaultTrue,
 		"prebuilts/tools/common/m2":                Bp2BuildDefaultTrue,
 
 		"system/apex":                                            Bp2BuildDefaultFalse, // TODO(b/207466993): flaky failures
@@ -273,6 +277,7 @@
 		"system/libprocinfo":                                     Bp2BuildDefaultTrue,
 		"system/libziparchive":                                   Bp2BuildDefaultTrueRecursively,
 		"system/logging":                                         Bp2BuildDefaultTrueRecursively,
+		"system/media":                                           Bp2BuildDefaultTrue,
 		"system/media/audio":                                     Bp2BuildDefaultTrueRecursively,
 		"system/media/audio_utils":                               Bp2BuildDefaultTrueRecursively,
 		"system/memory/libion":                                   Bp2BuildDefaultTrueRecursively,
@@ -492,6 +497,7 @@
 	}
 
 	Bp2buildModuleTypeAlwaysConvertList = []string{
+		"license",
 		"linker_config",
 		"java_import",
 		"java_import_host",