wcm.io Content Package Maven Plugin: Delay package install when bundles are still starting/stopping

etugarev provided a patch to the wcm.io content package plugin:
https://github.com/wcm-io/wcm-io/pull/15

this patch adds a new (optional) feature to automatically check the current bundle state, and delay the package installation if bundles are still in starting/stopping state e.g. from the previous bundle installation in a batch of packages that where uploaded. thanks for contributing!

this ticket is around finalizing and fine-tuning this feature.