Sync environment and application state with the cloud

[vikomall]

Repro instructions:

1. Create env
2. Create app
3. Delete AWS resources manually
4. Delete app results in following error
   ServiceNotFoundException: An error occurred (ServiceNotFoundException) when calling the DeleteService operation: Service not found.

[devdattakulkarni]

Thanks!

One way to fix this is to handle such exceptions gracefully and continue deletion of other application artifacts.

Another approach is to periodically sync the state of environment and application resources in AWS with those in cloudark. If any resource is missing then the corresponding env/app can be marked as degraded (or proactively deleted).

[devdattakulkarni]

Changed Issue title.

Currently cld will gracefully handle exceptions and continue deleting the application.

In the long term we should consider adding periodic sync of CloudARK's internal state with that of the Cloud.