Remove submit button for observations in book notes modal

[jimchamp]

Closes #

Observations are now POSTed to the server every time an input is checked or unchecked in the book notes modal. A section-level submission indicator is displayed in order to notify patrons of the submission status.

Details sections in observations form are also now open by default.

Technical

Testing

While logged in as a beta-tester:

1. Navigate to a book page.
2. Open the book notes modal.
3. Click on any observation radio button or checkbox.
4. Ensure that you receive a success message.
5. Refresh the page.
6. Open the modal again, ensuring that the previously selected radio button or checkbox is selected.

Screenshot

Successful submission:

Failed submission:

Note: Timeout added in above examples to better show the pending indicator.

Stakeholders

@mekarpeles
@cdrini

[mekarpeles]

This code is fairly well isolated (outside of the db interactions, which seem fine) and so I'm happy for it to be merged as is. UI seems like an improvement. This feature won't work with js, but that's life.