Release notes aggregator

Based on customer feedback from Iron Bank, we sometimes miss important changes coming into Big Bang releases in the release notes. And, it is difficult to go read release notes for each and every package.

To prevent this, BB would need a release notes aggregator script that creates the baseline for the BB release notes. The script would need to do the following:

• Compare the git chart versions from the last Big Bang release to the current branch to identify all differences in package charts
• Based on the chart differences, retrieve the package release notes for all chart revisions between the last Big Bang release and current branch. Add these to the release notes.
• Identify if the application version changed in each package's Chart.yaml. If so, retrieve links to all release notes for the package. Add release note entries
• Inspect all commits to Big Bang since last release. If changes were made to anything but values.yaml, add the commit message to the release notes. Values.yaml is ignored since the majority of those are going to be version bumps of packages.

The release notes that this spits out could then be updated by the release engineer as needed.

Data standardization for Big Bang packages. Chart.yaml now has the application versions set inside the annotations tag. This change allows future automation endeavors a one place look up for relevant data about the package. This is especially important for packages with multiple application versions we want to track. https://repo1.dso.mil/platform-one/big-bang/bigbang/-/issues/1063