Disable the maven site plugin for the LRA module

The narayana code coverage profile invokes the maven site goal so that the output can be viewed easily.

Now LRA relies on microprofile-lra-api snapshot builds but the site plugin appears to resolve to the latest snapshot (rather than a particular snapshot build) and since microprofile-lra-api regularly undergoes changes there are compilation failures.

This JIRA proposes that we disable the site plugin for the LRA module.