Add support for nexus.vmoptions settings

[AlexeiZenin]

Currently the Ansible role allows configuring JVM memory but it would be beneficial if we could add any arbitrary JVM option as shown here: https://help.sonatype.com/repomanager3/installation/configuring-the-runtime-environment

This is needed for hypertuning and adding javaagents (e.g. Datadog) to be able to do finer grain monitoring of the Nexus instance.