Memoize app_event_repository instance

  * this is currently needed for testing

Signed-off-by: Aram Price <aprice@pivotallabs.com>
Move app.update loggregator message to AppEventRepository

Signed-off-by: Aram Price <aprice@pivotallabs.com>
Move loggregator emit message on app create to AppEventRepository

Signed-off-by: Aram Price <aprice@pivotallabs.com>
Move loggregator emit message on app delete to AppEventRepository

Signed-off-by: Aram Price <aprice@pivotallabs.com>
Emit loggregator message on app exit

[#61987212]

Signed-off-by: Aram Price <aprice@pivotallabs.com>
Fix test to check parameter attributes

The Sequel "reload" updates the object and simple comparison fails
although all attributes are the same. Instead we only compare app guid
and updated attributes.