Add more specific subtitles and lyrics MIME types.

"srt" subtitles have a more specific MIME type of
"application/x-subrip", as listed here in Apache and therefore widely
used across the Internet:

http://svn.apache.org/repos/asf/httpd/httpd/branches/1.3.x/conf/mime.types

"lrc" lyrics have a more specific MIME type of
"application/lrc", as determined here from the archive.org scraping
of popular Internet sites:

https://discuss.httparchive.org/t/keeping-etc-mime-types-up-to-date/825

Bug: 143707020
Test: atest --test-mapping packages/providers/MediaProvider
Change-Id: I9598d1de920f29fbda7efa3c17b5632f756a65f2