Disscussion editor is rendered for every note, should be rendered 1 time per page

The discussion editor is rendered as a hidden element for each note if you are master. It should be rendered 1 time.

1. Discussion note should only be visible 1 at a time.
2. If you edit one note and go to edit another note only 1 should be visible so current should close and new should open.
3. If you already have something edited for the old note you should be prompted to finish editing first then edit new note. (Like Slack does).
4. Create 1 editable field per page. Move DOM element around.

cc @iamphill @alfredo1 @yorickpeterse