Introduce release & release notes

[arthurdm]

There have been a few requests to have release notes where one could read about what enhancements were made between images.

This can include:

• changes we've done directly to the image (e.g. improving SCC, permissions, etc)
• link to the corresponding Liberty's version release notes
• snapshot of which OS and Java versions are being picked up for the image
  • bonus points here would be if there was a way to indicate what changes those layers introduced, but may be tough because they don't have corresponding release notes themselves.