Draw Page: Add Annotation Support

[rajadain]

Overview

Validators should have the ability to add annotations to a submission:

• Add Annotation endpoints
• There should be an Annotate button in the Draw Toolbar that is only visible to Validators during Review
• Clicking it should put the map in "Annotation Mode" where the mouse cursor becomes a crosshairs
• Clicking a spot on the map should open a modal for adding a note:
  
• Clicking Back in the modal should "do nothing", so no annotation is added and the map is no longer in Annotation Mode, i.e. the cursor is now normal
• Clicking Save in the modal should add an Annotation to the map, and save it to the database
• Clicking the annotation should open a popup with View and Delete buttons:
  
• Clicking View should open up the modal from before, allowing the user to further edit the message. If they click Save, the annotation should be updated. If they click Back, the modal should be dismissed.
• If the click Delete, a modal should popup with the annotation details, and have a Delete and Back button. Clicking Delete should delete the annotation, clicking Back should dismiss the modal.
• Contributors should be able to only view annotations, and not delete them: