Modifies the edit section name field to be accessible

Adds an aria-label for screenreaders and overrides the default id
to keep it from conflicting with the create section input. Localizes
the label as well as updates the tests.

fixes CNVS-14482

test plan:
   - Go to a course settings page and click on the sections tab
   - Add a section
   - Edit a section
   - This should work without problem
   - Use a screenreader to navigate to the added section
   - The screenreader should indicate to edit the section name
   - Navigate to the add section field
   - The screenreader should indicate this as adding a section.

Change-Id: I8eef887948fd728e3a104eb8c0b72d0a1a4e977c
Reviewed-on: https://gerrit.instructure.com/38875
Reviewed-by: Jeremy Stanley <jeremy@instructure.com>
Tested-by: Jenkins <jenkins@instructure.com>
QA-Review: Clare Strong <clare@instructure.com>
Product-Review: Matt Fairbourn <mfairbourn@instructure.com>