Bug 6815: Capture member photo via webcam

Bug 6815: Capture member photo via webcam

This patch builds on a patch by Mark Tompsett, adding the option to take
a patron's picture using the computer's webcam. The photo can then be
saved to the patron's account.

To test, apply the patch and rebuild the staff interface CSS
(https://wiki.koha-community.org/wiki/Working_with_SCSS_in_the_OPAC_and_staff_client).

- Go to Administration -> System preferences and enable the
  'patronimages' preference.
- View a patron record. In the sidebar, hover your mouse over the blank
  patron image. Click the "Edit" button which appears.
- A modal window should appear with two sections, "Upload patron photo"
  and "Take patron photo."
  - If your computer has a webcam, your browser should ask permission to
    access it. Grant access.
  - You should see the view of your webcam shown under the "Take photo"
    button.
  - Click the "Take photo" button. The captured photo should be shown in
    place of the live video from the webcam.
  - You should now see three buttons: "Retake photo," "Download photo,"
    and "Upload photo."
    - Clicking "Retake photo" should hide those buttons and return you
      to a live video view.
    - Clicking "Download" should make your browser download the image.
    - Clicking "Upload" should cause the page to redirect back to the
      patron detail page where you should see the new patron image
      displayed in the sidebar.
    - Trigger the modal again and click the "cancel" button. The
      modal should disappear and camera access should stop.
- If your computer has no webcam the modal should appear correctly but
  there should be a banner at the bottom indicating that a camera is not
  available.
- Try the test again but this time deny your browser access to the
  webcam. You may need to reset the camera permissions in your browser's
  settings. When the modal appears you should see a message saying
  access to the camera is denied.
- The patron image edit modal should be available on all pages which
  show the patron image in the sidebar: Check out, Batch check out,
  Details, Accounting, Routing lists, Circulation history, Holds
  history, Modification log, Notices, Statistics, Files, Purchase
  suggestions, Discharges, Housebound, and ILL requests history.
- Test adding an image to a patron record using the "Upload photo"
  option. It should still work correctly.
- If the patron has an image attached, the "Upload photo" section should
  have a "Delete" button. Test that it works correctly.

Signed-off-by: Nicolas Legrand <nicolas.legrand@bulac.fr>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
Signed-off-by: Fridolin Somers <fridolin.somers@biblibre.com>