Adding tags to packages

[Pjotr Prins]

I don't know it this has been discussed before, but it would be useful
to have an optional tagging system. I would like to mark packages that
are useful for bioinformatics which can be outside the
bioinformatics.scm. Likewise it would be useful to mark packages that
are security related, network related, desktop related, x11 related
etc.

I propose an open metadata tagging system where package maintainers
can just enter any keyword in a list. Like the license tag, they can
be approved by GNU Guix and have metadescriptions somewhere.

This is about searching for information. One useful output would be to
present collections of packages on the www or in RDF/JSON.

Pj.