Validation Chain Model: SHELL, CHAIN, HYBRID + FileCache nextUpdate
Created by: ankex
- merge with branch develop, stand 01.03.2019
- added validation based model (chain, shell (default), hybrid) + junit & test data
- added validation model SHELL as comment within default validation policy /validation-policy/src/main/resources/policy/constraint.xml
- added nextUpdate implementation for FileCache usage
- minor NPE fixes