map-source: Make this class capable

Remove tile-source as there was no gain having a distinction between the two
1 job for tintou/no-tile-source in 1 minute and 34 seconds (queued for 4 seconds)
latest
Status Job ID Name Coverage
  Build
failed #1341867
fedora

00:01:34

 
Name Stage Failure
failed
fedora Build
ERROR: Error in gtkdoc helper script:

ERROR: ['/usr/bin/gtkdoc-mkhtml', '--path=/builds/GNOME/libshumate/docs/reference:/builds/GNOME/libshumate/_build/docs/reference', 'shumate', '../libshumate-docs.sgml'] failed with status 6
warning: failed to load external entity "../xml/shumate-tile-source.xml"
../libshumate-docs.sgml:79: element include: XInclude error : could not load ../xml/shumate-tile-source.xml, and no fallback was found

ninja: build stopped: subcommand failed.
Cleaning up file based variables
ERROR: Job failed: exit code 1