Logic function for getting a user's public activity stream

[seanh]

Add a function to logic.action.get that returns a user's public activity stream as a list of dicts/

Estimate: 0.5 days.

[seanh]

This ticket is just for getting the activity stream at the model level, not yet for rendering it in any particular output format.

Estimate: one day

Related user stories:

#039 User I want to see the activity stream for another user when I go to their user (profile/home) page.

#042 User Subscribe to RSS feeds for activity in relation to packages, users, groups, tags (?)

#032 User See what status people have by seeing small bits of info next to their name, e.g. a sign to indicate being a superuser/sysadmin and/or the number of datasets they have. I know the approximate activity and authority of users I come across

Also see: ​http://ckan.okfnpad.org/notifications

[seanh]

Should be as a list of dicts, not Activity objects.