Allow user-defined tokens in ivyLayout pattern.

[lourot]

This PR adds the possibility to use user-defined ivy tokens in the path where ivy.xml will be pushed to Artifactory. The DSL looks like

artifactory {
    publish {
        repository {
            ivy {
                ivyLayout = "[organization]/[module]/[myGreatToken]/[revision]/ivy-[revision].xml"
            }
        }
    }
}

// ...

publishing.publications.create("Ivy_myGreatPublication", IvyPublication) {
    organisation = "com.tomtom"
    descriptor.extraInfo("dummy", "myGreatToken", "myGreatValue")
}

dummy is a so-called "namespace", that isn't taken into account when resolving the layout. The DSL forces us to provide one though, see https://docs.gradle.org/2.7/javadoc/org/gradle/api/publish/ivy/IvyModuleDescriptorSpec.html .

As a side effect, the produced ivy.xml contains:

  <info organisation="com.tomtom" module="myGreatModule" revision="1.0.2-SNAPSHOT" status="snapshot" publication="20150921173700">
    <ns:myGreatToken xmlns:ns="dummy">myGreatValue</ns:myGreatToken>
  </info>

A TomTom-internal review has already been performed by @maikelvdh and @ffung, see https://github.com/AurelienLourot/build-info/pull/1 .
@martinm82, you might also be interested.

[lourot]

Thanks for merging!

[eyalbe4]

Sure this @AurelienLourot .
Thanks a lot for this great contribution.
This Jira issue! tracks this code merge,