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.

(While cherry-picking, s/29/apex_inherit)

Bug: 152655956
Test: m
Merged-In: I90e135617642c87ecff517a17120285d8355827e
Change-Id: I90e135617642c87ecff517a17120285d8355827e
(cherry picked from commit 6732ec8048569ddc4b2a3d18b1c42dabfa7ad4bc)

Android.bp

diff --git a/Android.bp b/Android.bp
index e170ca0..8fb5ad9 100644
--- a/Android.bp
+++ b/Android.bp
@@ -44,4 +44,5 @@
     ],
 
     export_include_dirs: ["inc"],
+    min_sdk_version: "apex_inherit",
 }