PluginVerifier should output into BuildArtifacts

[nils-a]

and be integrated in the issues report.

Output folder can be directed using the -verification-reports-dir (-vrd) option

Currently results of the verifier are placed human readable in a folder structure and the existence of specific files points to success or failure:

Note! If you are implementing integration with the Plugin Verifier, you may check the presence of corresponding files to distinguish "successful" and "failed" verifications.

There is an issue towards machine readable format.