Create publishing tasks and software component for XTC artifacts

[lagergren]

For example, we may want to publish the platform and its modules to a remote artefact repository, just like we do with the xtc plugin and the xdk.

Hence we need to add a Gradle software component for XTC modules, and a publishing task.

This means that we can request things like the "platform" and its modules from a repository, which should make it very simple to create a "prod" container for the platform without having to add a lot of logic that clones and builds source, gradle installations and so on.