stream: Fix track conversion bug and add tests

This adds basic checks for the library provider lookup:

- Check that uri schemes are respected
- Check that blacklisting and globbing works
- Check uri successfully gets converted to a track
audio: Move utils test to tests folder
audio: Only add albums that have a name

Fixes case where we could have an empty album. We could alternatively be more
conservative and only limit to fully empty albums. But I think we only want
ones with names anyway.