fix null pointer when tags are used in search
Merge branch 'dev' of github.com:iPlantCollaborativeOpenSource/DiscoveryEnvironment into dev
CORE-6037 fix issue with sending gff file to Ensembl.
CORE-6026 fix preferences validation logic.
core-6041 update text for 'send to ensembl'
Updated logging to use logback. Logging messages for DEServiceImpl and apache http now prepended with user name.
Added logger config for http headers only
core-6029 clear tags in view when clearing advanced search
Added null check to username logging MDC data
CORE-5960 Initial update of apps/categories endpionts
CORE-5960: Rename App/AnalysisGroup to AppCategory
CORE-5960: Adding new app endpoint
Also performed some renaming of legacy method signatures which still used "analysisId" vs "appId"