Provide option to run LT plugin stop comand when the stop action is used

[mezarin]

This PR attempts to provide a workaround for the issue where the start action is run on a project, but it fails because there is a Liberty server already running perhaps due of a prior unexpected session failure or user action.

The workaround allows users to run the Liberty Tools stop action to stop a Liberty server running the project outside of a Liberty tools session. The Liberty Maven/Gradle plugin stop command is issued to stop the Liberty server.

Since stop is issued in an unconventional way, a choice dialog is displayed to let the user know that the session for the project in question is not active or has not been initialized (start/debug), and to give the user the choice to run the LMP/LGP stop command or not.

For example:

[scottkurz]

One change I think we need is to set JAVA_HOME in the new process. I only thought of that because this fix didn't work in my env.

Maybe something like
pb.environment().put("JAVA_HOME", JavaRuntime.getDefaultVMInstall().getInstallLocation().getAbsolutePath());
or possibly we only want to set if it's not already set??? Will have to think about it.

[scottkurz]

Superseded by #412