Wrap process changes in a locked transaction

[#79386676]
Fix unexpected modification on updating processes through repository

[#79386676]
Operator switching CC Diego flags correctly switches behaviour of apps

Also, refactor bulk endpoints to use backends
Simplify Backends interface, validate StagingCompletion only handles Diego apps.
Refactor Backends into three

* Stagers - know about staging
* Runners - know about running
* InstancesReporters - know how to report

HM9000 needs to check for Diego on stop app

* When Diego is enabled, the HM9000 needs to stop any app that is marked
* for running on Diego.
[#80165482]

Signed-off-by: Nick Wade <nwade@pivotal.io>
refactor app observer specs [#76898498]

Signed-off-by: Nick Wade <nwade@pivotal.io>
Revert "Avoid time zone and DST-related bugs by switching to Time.current."

This reverts commit 2259b62ead84465b3871d66ef666d9e2d17bbce9.

Conflicts:
	spec/unit/lib/cloud_controller/diego/staged_apps_query_spec.rb
add package_pending_since field to app model

 - package_pending_since gets updated everytime a package is marked as pending
 - package_pending_since is cleared (set to NULL) when package state
 chagnes to anything that isn't PENDING

[#80259334]

Signed-off-by: Johannes Petzold <jpetzold@pivotal.io>
periodically clean up packages that have been pending for too long

[#80259334]

Signed-off-by: Johannes Petzold <jpetzold@pivotal.io>
staging complete handlers fail if staging was already marked as failed

- for DEA and Diego
- staging could be marked as failed due to having been cleaned up by the pending package cleanup job

[#80259334]

Signed-off-by: Luan Santos <lsantos@pivotal.io>
Add audit events for copy bits operation on src and dest apps.
[#81647606]
Remove NFS management from CC API and Worker

[#77227116]
Set default request_timeout_in_seconds to 900s (15min).

[#80931258]
Fixes to /v2/service_instances/:guid docs

[#76633662]
Add StagingTimeExpired error to staging_failed_reasons

[#80259334]
Fix src and dest app order for copy bits events.

[#81647606]
Handle local blobstore for api and worker.

[#77227116]
WIP: Fixing specs for api v2.4 service instance plan update [#71061338]