Kill media-storage thumbs server

They haven't been used in production for a while and there's no point in
leaving this cruft behind, especially now that we have a modularization
effort. If we ever need this again, there's always the git history :)

Change-Id: I350d97782dde750c8f87dfe52a81460cff2c444f
Merge "Kill media-storage thumbs server" into production