Why is lastfm a required dependency?

[Nikolaj Hald Nielsen]

I have spent quite some time getting all last.fm related code out of
the core of Amarok (libamarok) and into the plugin, even creating a
few system for plugins to add user interface elements to all tracks
and such, this means that currently, if the service is not present, it
will not leave any traces in the code or the user interface.

I think it makes sense to leave this optional in the same way that the
mp3tunes service is not build if the loudmouth dependency is not
installed and so on. A basic premise of the services was that they
should be easily removable if the online service turns evil, a distro
has ethical/legal/technical issues with it and that removing them
should not leave any residue behind.

So I am for making it optional, but mostly for purely philosophical reasons.

- Nikolaj