Add CLI args to skip in Maven plugin

Now that `-Djib.skip ` supports skipping jib builds, configuring `skip` in `pom.xml` will skip submodule jib builds, is it possible to support skipping modules on the command line, for example

```bash
mvn package \
com.google.cloud.tools:jib-maven-plugin:3.2.1:build \
-pl hello-service \
-Djib.skip.pl=hello1-service,hello2-service
```

Then all the operations supported by `jib` can be specified on the command line without modifying `pom.xml`