Create a Knowledge Base Article based on the content about containerization rules

There is a great contribution as documentation about the MTA rules for containerization by akrohg@redhat.com here: https://gist.github.com/andykrohg/18dfa167f01c529b8a2f23a729091302

Having that content as a maintained official document to be referenced would help MTA users. 

Initial choice would be to put it in a KBase article 

akrohg@redhat.com already agreed with us to use the content (Thanks a Bunch!)