Carry app staging failure reason into ccdb

Improve the end user experience by providing a detailed message when
no buildpack detected an application.

* Add staging_failed_reason column to app to hold error key for well
  known staging errors.
* Populate staging failed reason with information from the staging
  response and use it when raising api errors from the instances
  endpoint.

[#68122384]
Merge pull request #241 from sykesm/detect-failure-message

Carry app staging failure reason into ccdb