Tag descriptions / Badge sets

[lmorchard]

This issue may highlight the need for a more explicit user-owned Badge set concept, for which tags are really just kind of a grouping hack. A Badge set would be created for an organization or an event, allow a delegate group, and maybe have a mechanism where badge creators can be asked whether or not they wish one or more of their badges to be included in the set.

Might be handy to enable a verbose description of a tag, display that on the tag page. This can help describe an event using the tag, or provide more context in general.

An issue is that tags belong to no one, so who has permission to edit the description? Maybe add support for a kind of tag owned by a user and a group of delegates. Those people could:

• edit the tag description,
• control access to add the tag to badges,
• use the tag to extend certain permissions over the tagged badges (eg. claim code access, etc)
• grant claims to badges in the tag / group

Not sure if this is overloading tags too much. Descriptions could be useful, at least.

[lmorchard]

I think the use cases for this are better served by explicit Organizations (#94) and Events (#95)