Move submission notes out of metadata and into the message list

[mccalluc]

• Move the message text area next to the message list (and change "comment" to "message") #814 should be reviewed and merged before reviewing this PR.
• This moves towards Put Notes in Messages #782 but doesn't fully address it.

This PR just moves the HTML around, but looking at the original issue:

• Curator receives a numbered notification if a note was included.
• The numbered notification resolves when a curator reads the note

To do all of that, we'll need to change the model code: should be possible, but it is more complicated.

If this seems valuable as a partial solution, it could be approved... but if it seems better to implement the full solution, then this could be closed.

[bess]

⭐ Looks great!

I made a separate ticket to refactor the code to use consistent language for message instead of comment: #825