PT-273/PT-450: Add support for rules as Maven artifact

[mr-archano]

Tracked by PT-450

Scope of the PR

We would like to provide a way to consume the same set of rules cross-projects for all the static analysis tools we intend to use. A viable way to share such rules is as maven artifact (JAR).

Considerations and implementation

Added a container of RulesExtension to StaticAnalysisExtension that can be used to define artifacts containing rules we want to use to configure the static analysis tools, eg:

staticAnalysis {
  rules {
    novoda {
      maven 'foo.bar:static-analysis-rules:0.1'
    }
  }
  checkstyle {
    config rules.novoda['checkstyle/modules.xml']
  }
}

where foo.bar:static-analysis-rules:0.1 is a JAR deployed to a maven repository of choice. The configuration XML file can be accessed via the getAt operator providing the relative path inside the JAR. It is then retrieved as TextResource that can be fed - for instance - to checkstyle.config or anywhere such type is supported.

Test(s) added

Added RulesIntegrationTest to check the new feature. To help with the setup we introduced a DeployRulesTestRule in order to create and then deploy a set of rules as JAR artifact into a local maven repo that can be used in the integration test.

[takecare]

fancy 👍

[tasomaniac]

So we are expecting multiple rules to be defined. Makes sense.

[frapontillo]

👍 from my shallow understanding of all of this.

[mr-archano]

Note: I went for the New Maven Publishing support. The old one I was used to has a problem with the generation of the metadata/pom file on the first run.

[tasomaniac]

Looks good. Would be good to ship it with sample and info on the README 👍

[devisnik]

Great to see rule sharing enabled at this level! 👍

[mr-archano]

@tasomaniac I thought about that, but I figured it would be weird to read in the README of an unreleased feature. I plan to amend the documentation as part of the preparation for next release.