Add ability to specify the output file name on the command line.

[gzsombor]

This is required, in a maven multi-module setup, where relative path could point
to different files, when started as a parent or a sub-module build.
With this change, in the pom.xml you can specify --outputFile ${basedir}/validation.json

[buildhive]

Netcetera » valdr-bean-validation #102 SUCCESS
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[coveralls]

Coverage increased (+0.15%) to 90.82% when pulling 341aca7 on gzsombor:output-file-name into f944d20 on netceteragroup:master.

[marcelstoer]

I'm going to change this so that passing -outputFile to the CLI overrules any outputFile which may have been set in valdr-bean-validation.json.

[gzsombor]

Good idea, thanks !