Using spotless-maven-plugin with Eclipse JDT behind custom P2 mirror

In our company we have the situation that we need to load the P2 artifacts required by Eclipse JDT from a custom JFrog Artifactory registry.
We have the following two issues:
1. The P2 mirror requires authentication. How can I set this via the plugin configuration?
2. We want to open source our Java project and therefore not include custom configuration in the `pom.xml`. When persons from outside the company pull our code from GitHub, they dont need the p2Mirror configuration. Is there a possibility to configure the P2 mirror via configuration files like `settings.xml` in Maven? Or maybe introduce environment variables the plugin checks to load from custom mirrors?

Thanks very much in advance!