Add android.sdk aconfig flags

Add the infrastructure for aconfig flags in the android.sdk package.
Also add the flag android.sdk.major_minor_versioning_scheme.

Bug: 350458259
Test: m nothing
Flag: EXEMPT no need to flag the introduction of new flags
Change-Id: I928b44dd802dc3d1351547d516d3c195329219a6
diff --git a/android-sdk-flags/flags.aconfig b/android-sdk-flags/flags.aconfig
new file mode 100644
index 0000000..cfe298e
--- /dev/null
+++ b/android-sdk-flags/flags.aconfig
@@ -0,0 +1,12 @@
+package: "android.sdk"
+container: "system"
+
+flag {
+    name: "major_minor_versioning_scheme"
+    namespace: "android_sdk"
+    description: "Use the new SDK major.minor versioning scheme (e.g. Android 40.1) which replaces the old single-integer scheme (e.g. Android 15)."
+    bug: "350458259"
+
+    # Use is_fixed_read_only because DeviceConfig may not be available when Build.VERSION_CODES is first accessed
+    is_fixed_read_only: true
+}