Add axion-release-plugin

I added new bare simple [release plugin](https://github.com/allegro/axion-release-plugin) for project who would like to follow Continuous Delivery - something for us. I was playing with it locally and looks fine. There are some issues, but author seems to be responsible.

Please make a review, read documentation and comment.

Please do NOT merge that branch. I will do that after manually release 0.3.0 with the new plugin.