pcp.user.actions - Decompose deviant list of links

pcp.user.actions - Decompose deviant list of links

The problem is that:

* `hook_links('pcp.user.actions')` fires with a malformed set links
* The malformed set of links has been specifically encoded into unit tests

So fixing the bad links would likely break some consumer. (I don't see the
consumer in my copy of `universe`, but if someone wrote the test, then they
must've really meant it...)

This patch adds alternative variants (`hook_links('pcp.user.actions.add')` and
`hook_links('pcp.user.actions.all')`) which should replace it.