Support git-notes

[bartkamphorst]

It would be helpful if RJGit would also support Git Notes. JGit has support for this feature:

• https://stackoverflow.com/questions/46167451/how-to-read-git-notes-using-jgit-given-a-commit-sha
• https://javadoc.io/doc/org.eclipse.jgit/org.eclipse.jgit/latest/org.eclipse.jgit/org/eclipse/jgit/notes/package-summary.html

[dometto]

🎆