alarm logic for NTEnums

[kathryn-baker]

Currently there isn't any logic in p4p_ext for setting Enums to alarm on a specific index or choice. This is a common use case as Enums are often used as flags to indicate issues and therefore would want to be associated with an alarm state.

Acceptance Criteria:

• new rule exists to handle enum alarm logic
• new rule is included in Enum related handlers if relevant
• methods are exposed to allow alarm configuration on Enum recipes
• config_parser knows how to deal with alarmed enums
• unit tests completed for new code
• integration tests for alarmed Enums