Deprecate the current concept of Roles in Crowd

Currently, roles in Crowd are just another container for users - just like groups.

In fact, in Crowd 2.0, roles were migrated to be implemented as groups, with a "LEGACY_ROLE" group type.

We should officially deprecate roles as they do not offer anything more than groups do, and contribute to confusion both within the code and to end users.

This will mean deprecating:

• role queries on the SOAP API
• the "LEGACY_ROLE" group type
• deprecating roles in the UI or putting some notice in the UI to state that roles should not be used, use groups instead