ASGARD-1056 Keep app instance cache when Eureka is sick

App instance cache should not become empty when
all Eureka instances are briefly unhealthy
added characterization tests
refactored FastProperty construction
less work should be done in constructors
use simplified FastProperty construction in tests
added FastProperty ID validation
Move XML creation into FastProperty
add Fast Property validation on creation
simplify tests post refactoring
ensuring constructor acts like toXml is less important after refactoring
added javadoc for getter
removed a field that is never used along with associated logic
ASGARD-1077 - Alarm state changes should trigger SNS for all state changes
isolate and characterize the existing behavior
give preference to returning UP instances if any exist
Merge pull request #224 from claymccoy/fastPropertyValidation

ASGARD-1018 - Fast property validation
Merge pull request #225 from claymccoy/AlarmSns

ASGARD-1077 - Alarm state changes should trigger SNS for all state changes
Only return running instances
Move logic to a service where it can be shared by controllers.
Look for healthy instances for autoscaling/anyInstance just like cluster/anyInstance.
ASGARD-909 More accurate http codes returned for anyInstance actions.