MediaScanner: Do separate bulk inserts for different media types

MediaScanner: Do separate bulk inserts for different media types

This should fix a bunch of problems introduced in the original bulk insert implementation

Also reverted two changes that are no longer necessary:

Revert "MediaScanner: Add virtual NO_MEDIA column to fix support for .nomedia files"

This reverts commit 92e1314ad9ddbacfb806405e9aceeea4a8aae19f.

Revert "MediaScanner: fix breakage in updates"

This reverts commit 45aaa2a345292bb6d600822db602f25e261c0e50.

Change-Id: Ibed66393467761c2c1ce48deb09bcac505b7d221