Document fields that aren't required on update

[#76159766]
Add staging behavior to backends

Also fixes regression in a feature to properly migrate DEA staged
apps (without a start command) to Diego

[#75217152]
Refactor AppObserver - Use the Backend abstraction

[#75217152]

Signed-off-by: Peter Parente <pparent@us.ibm.com>
Update API docs to scope Quota Definition to an Organization

- update API DSL helpers to take title override
- base title default on path in list and get helpers
- base title default on model in delete helper

[#76311006]
Add ability to list spaces that relate to a Space Quota Definition

[#76159856]
Move dea advertisement subscription to stager_pool

[#75217152]

Signed-off-by: Peter Parente <pparent@us.ibm.com>
Remove unused method

[#75217152]

Signed-off-by: Peter Parente <pparent@us.ibm.com>
Add `docker_image` to app table, model, controller

API spec is updated with experimental support for docker images

[#75217152]

Signed-off-by: Peter Parente <pparent@us.ibm.com>
Avoid nil start commands when droplet is missing

Signed-off-by: Peter Parente <pparent@us.ibm.com>
Allow service plans to be queried by service guid when not authenticated

[#76020926]
Added access control to individual fields for model api.

[#75649630]

Signed-off-by: Luan Santos <lsantos@pivotallabs.com>
Signed-off-by: Michael Fraenkel <fraenkel@us.ibm.com>
wip
wip part deux
wip part trois
wip part quatre
wip part next
wip no one is counting
Took long enough for all access to pass