Migrate ringtone picking out of MediaProvider.

Some OEMs have requested the ability to customize the ringtone
picker logic, and that's already supported by the existing
"config_defaultRingtonePickerEnabled" parameter today.

This change is a clean refactoring of the AOSP ringtone picker out
of MediaProvider and into a new "SoundPicker" module, which is
consistent with how some OEMs have already defined their own
"SoundPickerPrebuilt" module.

Bug: 134542205
Test: atest --test-mapping packages/providers/MediaProvider
Change-Id: Iadc60e731e6dcfce651f89bc7598e65541ab0ddf
diff --git a/packages/SoundPicker/Android.bp b/packages/SoundPicker/Android.bp
new file mode 100644
index 0000000..3be7ca9
--- /dev/null
+++ b/packages/SoundPicker/Android.bp
@@ -0,0 +1,18 @@
+android_app {
+    name: "SoundPicker",
+    manifest: "AndroidManifest.xml",
+
+    static_libs: [
+        "androidx.appcompat_appcompat",
+    ],
+    resource_dirs: [
+        "res",
+    ],
+    srcs: [
+        "src/**/*.java",
+    ],
+
+    platform_apis: true,
+    certificate: "media",
+    privileged: true,
+}