Add getParameter(String) to MarketplaceEntry.
MarketplacePortletDefinition depends on IMarketplaceService.

Dependency fulfilled via constructor injection.
MarketplaceEntry is aware of the user for whom it is instantiated.

Takes the user via constructor injection.
MarketplaceEntries were already implicitly per-user given their
user-specific property ( 	`isCanAdd` ).
Filter MarketplacePortletDefinition random relateds by BROWSE.

 * MarketplacePortletDefinition random sampling of related portlets
filters by user.
 * MarketplacePortlet switches to using MarketplaceEntry
rather than MarketplacePortletDefinition.
 * IMarketplaceService method to get featured MarketplaceEntries.
UP-4326 add MarketplacePortletDefinition equals() and hashCode().
Merge pull request #481 from apetro/UP-4320v3

UP-4320 enforce BROWSE permission on related portlets in Marketplace.