Integrate MRI projects for Neon

Integrate MRI projects for Neon

This patch bumps:
- odlparent to 4.0.2
- yangtools to 2.1.2
- mdsal to 3.0.1

It deals with the fallout in following ways:
- xmlunit -> xmlunit-legacy
- fix unstubbed methods
- migrate to java.util.Optional where needed
- update test data to account for automatic list removal
- update to sshd-2.0.0
- account for ietf-{inet,yang}-types moving
- remove explicit null in blueprint
- use isNull() instead of any(Class<T>) where we want to match null
- prevent UnnecessaryStubbingException in TestRestconfUtils class
- remove jersey-related version overrides
- reuse NoOpListenerRegistration

JIRA: NETCONF-555
JIRA: NETCONF-564
Change-Id: Ib2b6bc8cfe868f1c268b243052429e6a10cfb5e8
Signed-off-by: Robert Varga <robert.varga@pantheon.tech>
Signed-off-by: Jakub Morvay <jmorvay@frinx.io>