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.

"apex_inherit" is a special alias to represent "the minimum of all
that the apexes require".

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

Bug: 152655956
Test: m
Change-Id: I23cb55a3a17ac242e7f599fe574ca30074b43506

Android.bp

@@ -61,6 +61,8 @@ cc_library_static {
         "//apex_available:platform",
         "//apex_available:anyapex",
     ],
+    // being part of updatable apexes, this should work on older releases
+    min_sdk_version: "apex_inherit",
     native_bridge_supported: true,
     srcs: [
         "src/algorithm.cpp",
@@ -122,6 +124,8 @@ cc_library_shared {
         "//apex_available:platform",
         "//apex_available:anyapex",
     ],
+    // being part of updatable apexes, this should work on older releases
+    min_sdk_version: "apex_inherit",
     whole_static_libs: ["libc++_static"],
     stl: "none",