For 7.2, we need to revise the currently supported Node.js versions for the Node.js adapter.

Tests for Node.js 4.4.2 started to fail with RH-SSO 7.2 so we need to decide if we should still support this version.
Specifically, GrantManager in public mode should be able to obtain a grant is failing on:

Grant validation failed. Reason: failed to load public key to verify token

Proposition: support the specific Node.js versions which are in the latest RHSCL: 4.6.2, 6.11.3 and 8.6.0.