DLUX upgrade to Neon SR2

DLUX upgrade to Neon SR2

Upgrade OpenDaylight upstream dependencies to Neon,
so that the project resolves and builds.

Upgrade frontend-plugin to 1.8.0, see
https://github.com/eirslett/frontend-maven-plugin/blob/master/CHANGELOG.md

Upgrade node.js to 12.13.0 (LTS).

Also mark some leftovers which need to happen for us to get on something
reasonably supported.

Change-Id: I656140b1361578741f4ba5879afbdb46c2c0b4d7
Signed-off-by: Rohan Julka <rohanjulka19@gmail.com>
Signed-off-by: Robert Varga <robert.varga@pantheon.tech>