OpenNMS Plugin API v1.6.0

What's Changed

• add IPLike (and InetAddressUtils) to OPA by @RangerRick in #81
• remove unnecessary uses of guava, hide transitive dependency by @RangerRick in #87
• NMS-15808: add new enlinkd protocols by @RangerRick in #92
• clean up some sonarlint warnings by @RangerRick in #103

Full Changelog: v1.5.0...v1.6.0