[Scenario] Use CostCapability in Activity Type repository

Repositories implemented for Activity Types and Tags
used capabilities to determine eligibility for object
containment. Fix for nasa/MCT-Plugins#119 split
existing CostFunctionCapability to add CostCapability
(which has no notion of change over time) which
was used by Activity Types. This broke some
functionality related to Activity Type repositories,
which is restored here by updating references
to the new capability type.
Merge pull request #122 from VWoeltjen/mctPlugins119b

[Scenario] Use CostCapability in Activity Type repository