Set min_sdk_version to be part of mainline modules

Modules contributing mainline modules (APK/APEX) should set
min_sdk_version as well as apex_available.

For now setting min_sdk_version doesn't change build outputs.
But build-time checks will be added soon.

From the perspective of Mainline modules, min_sdk_version should
be equal to or less than "29"(com.android.media). However, quick
code-search revealed that the minimum of min_sdk_versions of modules
depending on this seems to be 14.

Bug: 152655956
Test: m
Merged-In: Ib53d23a26ecebca4abcebedc4d4ba7cecc2119cb
Change-Id: Ib53d23a26ecebca4abcebedc4d4ba7cecc2119cb
(cherry picked from commit 459aacf9428125a06a2092cc48b14bb3710b49fd)
diff --git a/Android.bp b/Android.bp
index 234a888..f612412 100644
--- a/Android.bp
+++ b/Android.bp
@@ -17,6 +17,11 @@
     host_supported: true,
     hostdex: true,
     sdk_version: "core_current",
+    apex_available: [
+        "//apex_available:platform",
+        "com.android.media",
+    ],
+    min_sdk_version: "14",
     srcs: ["ri/src/main/java/**/*.java"],
 }