feat(dal, sdf): Add ability to create a note on the diagram

[stack72]

This creates a content node on the snapshot for the changeset and it can be merged to HEAD

There is absolutely no UI implemention for this yet - it's purely an idea that we can explore. But my imagination is that we can right click on the diagram and add a note - a note has a string for it's conents and a position - nothing more at this time and there is no connection between a note and a component at this time