JavaReflection: Dynamic check loading

[v1v]

JenkinsLintAction class is the root class. But does it make sense to instance new Checks explicitly or it is worth to use Reflection and load all those classes under org.jenkins.ci.plugins.jenkinslint.check?

Let's refactor this plugin and enable this feature.

[v1v]

I'm not sure whether using a third party library might help to avoid explicitly defining those checks...