[Scenario] Give repository info to Activity wizard

Provide information about relevant repositories
(Activity Types, Tags) to the Activity creation
wizard upon instantiation; this will permit
subsequent creation of appropriate tag selection
dialogs.

Additionally, this is useful for programmatically
populating the wizard's UI itself (based on
relevant repositories, rather than hard coded.)
[Scenario] Show tag selectors from Activity wizard
[Scenario] Make tag/type associations in Activity wizard

Add tag/type associations selected using tag selection
dialogs to the created Activity, from the Activity
wizard. This completes introduction of functionality
for nasa/MCT-Plugins#133.