Better config.json error handling
Better config.json error handling

Based on feedback from @danmick we're simplifying errors on config.json

- it is now entirely optional. The defaults should be safe for most
  installs
- if there is no json file it just uses defaults, this is no longer an
  error
- if there is a json file and it contains errors, it triggers an
  notification on the UI informing the user but continues using
  defaults.
- moved the merging of the config file to after the error handling,
  otherwise it would never fire because it was part of the same .then()
  clause and therefore parallel
- introduced a wait after loaded function to send the app:configerror
  event after the application has been correctly started
- add a handler for app:configerror to AlertView to display the message
  from config-loader.js as an error.

GregMeno/test,SUSE/romana,ceph/calamari-clients,SUSE/romana,ceph/romana,ceph/calamari-clients,SUSE/romana,SUSE/romana,ceph/romana,SUSE/calamari-clients,SUSE/romana,SUSE/calamari-clients,GregMeno/test,ceph/romana,SUSE/calamari-clients,SUSE/calamari-clients,ceph/romana,GregMeno/test,ceph/romana,ceph/calamari-clients,GregMeno/test,SUSE/calamari-clients,ceph/calamari-clients,GregMeno/test,ceph/calamari-clients