[Experimental] Provide a cool boot message

We should have a way to display a cool ASCII message in the boot traces.
The goal of this feature is to provide a way to display a cool banner ASCII art message in the console when the server starts.
This banner should be optional so we want to be able to not provision it and have no issue.
If the banner.txt file is not present then we shouldn't fail and just not display the banner.
As it is an experimental feature, if the stability level is higher then the banner shouldn't be applied.
The banner.txt should contain some ASCII art text in UTF-8.
The banner is an internal detail so we wouldn't want it to be another file in the bin folder. It should be considered a part of the 'product' module.

SME: bstansbe@redhat.com