So now we've got a component receiving records (goals or targets) and a
related model (Debate, Proposal, ...), with optionally a link to see
more tags.
This way we simplify some logic since the `TagList` classes were dealing
with too many cases (a record is passed, a class name is passed, a limit
is passed), ... Now `TagList` only deal with the natural `TagList` case,
which is listing the tags for a record. The case where a class name is
passed is used in the `TagCloud` class.
