secured-route configuration is now delayed

secured route configuration is delayed until after the properties have been loaded.
CORE-5048 externalizing search configuration
CORE-5048 refactored client-side error responses
Merge branch 'dev' of https://github.com/iPlantCollaborativeOpenSource/Donkey into dev
CORE-5048 implemented more error responses

Invalid queries now respond with an INVALID_ARGUMENT.

ElasticSearch connection failures and configuration errors result in a server error ERR_CONFIG_INVALID.
Merge remote-tracking branch 'origin/dev' into dev