Actions runHook on worker

This change adds the ability for Actions to be run on a charm using the
same logic used for Hooks.  The Action is run in the "actions" location on the
charm.

A second PR will address Action param Validate.
Removed ActionName and ActionParams from worker/uniter/hook.Info
Pending actions added to worker uniter test
Updated juju/charm dependency to include testable charm with actions location