[LSC] Add LOCAL_LICENSE_KINDS to system/sepolicy

Added SPDX-license-identifier-Apache-2.0 to:
  build/Android.bp
  build/soong/Android.bp
  tests/Android.bp
  tools/Android.bp

Added SPDX-license-identifier-Apache-2.0 legacy_unencumbered to:
  Android.bp
  Android.mk
  compat.mk
  contexts_tests.mk
  mac_permissions.mk
  seapp_contexts.mk
  treble_sepolicy_tests_for_release.mk

Added legacy_unencumbered to:
  apex/Android.bp
  tools/sepolicy-analyze/Android.bp

Bug: 68860345
Bug: 151177513
Bug: 151953481

Test: m all

Exempt-From-Owner-Approval: janitorial work
Change-Id: I1ab286543ef1bdcb494cf74f2b35e35a08225d28
diff --git a/apex/Android.bp b/apex/Android.bp
index 762dd54..2ffaa9e 100644
--- a/apex/Android.bp
+++ b/apex/Android.bp
@@ -13,6 +13,14 @@
 // limitations under the License.
 
 
+package {
+    // http://go/android-license-faq
+    // A large-scale-change added 'default_applicable_licenses' to import
+    // the below license kinds from "system_sepolicy_license":
+    //   legacy_unencumbered
+    default_applicable_licenses: ["system_sepolicy_license"],
+}
+
 filegroup {
   name: "apex.test-file_contexts",
   srcs: [