Overriding modernizer-plugin config in jclouds-resources

This fixes a self-dependency
Moving checkstyle-plugin config to profiles
Overriding checkstyle-plugin config in jclouds-resources

Otherwise, fails with a self-dependency
Revert "JCLOUDS-736: Revert "Fail build on checkstyle warnings""

This reverts commit 80d51f409aa36f1a5505214eb4ac6e1128213c92.
Using net.java.dev.jna:jna 4.0.0 for jsch.agentproxy

The default version 3.4.0 is only LGPL-licensed.

This commit can be reverted once SMX4-1859 is published and we can
update to 0.0.8 agentproxy versions.
Cleaning up formatting in project POM
Moving the invocation of checkstyle:check from 'validate' to 'verify'

Also removing the *additional* invocation of checkstyle:check, which
was unnecessary and caused builds to break into the bargain.