Go/No-Go vote for making Sodium a Java 11-only release

There is a discussion about how we are transition to Java 11 here: https://lists.opendaylight.org/pipermail/tsc/2019-January/010840.html , with one of the options is to make Sodium require Java 11 to build and run.

If we are to implement that option, the TSC needs to make JDK11 compatibility a requirement for participation in Sodium Simultaneous Release, which needs to happen before the release officially opens, i.e. on March 7th at the latest.