[Spring Boot] Added Spring Data REST client.
[Spring Boot] Added Resource DTO.
Upgraded Spring Boot version.
Added Lombok to Spring Boot Data.
More lombok for Spring Boot Data.
Fix memory retaining by clearing listeners in groups.

The group listeners usually contain references to the bundle using the group, and given zk watches are kept in memory, we need to remove those references.
Fix fabric8-karaf distribution which is missing a file, leading to failures to provision remote ssh containers
Fix timestamp formatting for insight metrics on elasticsearch
Avoid possible NPE
Fix memory problem to remove a reference to ES when the servlet is destroyed.

The servlet is retained by pax-web servlet events.
[FABRIC-171] maven-proxy will work behind secure http proxy after fixing WAGON-416 (test case)
[FABRIC-780] Allow fabric-agent to use proxy configuration from settings.xml
[FABRIC-171] Fix test for authenticated http proxy
[ENTESB-1666] Correct order of completers for fabric:container-upgrade
[ENTESB-1666] Correct order of completers for fabric:container-rollback
[ENTESB-1332][ENTESB-1405] Correct way of removing remote branch for version in GitDataStore
[FABRIC-780] Use provided settings (empty) instead of relying on external file
fixes #1509 so we can configure the context path for wars (when not explcitily doing so inside the war using a container specific config file)