New hotspots: load profiles and async search

Adds two new hotspots

Custom load_profile

Uses a custom rule to load profiles on Noosfero controllers. Only used if no profile was found using the method from the core.

Async search

Enables plugins to submit jobs for certain searches. The view will wait and display a searching cursor while these jobs fetch for content in background, and will automatically update when all jobs finish. It is useful if you want to fetch for assets using operations that should not be performed in foreground, like querying remote servers.