Move default ringtone configuration to framework.

This ensures that partners have a place to customize the default
ringtone configuration, such as adding support for per-SIM ringtones
which aren't officially supported by Android yet.

Bug: 141596983, 141518853, 141594113, 141595768, 141809410
Test: atest --test-mapping packages/providers/MediaProvider
Change-Id: Ibe5b41c09ca40caadfcbb81162b996173fe8509b