Bug 31419: Add accesskeys for modals

Bug 31419: Add accesskeys for modals

This patch simply adds accesskey elements to the buttons, and changes an icon to be
consistent with bug 26626

For tips on how to access the accesskeys:
https://developer.mozilla.org/en-US/docs/Web/HTML/Global_attributes/accesskey

To test:
1 - Generate a recall
2 - Fill it/check in
3 - Note modal now has hints "Confirm (Y)"
4 - Test with Y,P,I keys (may need to recreate recalls)
5 - Confirm the recall and test waiting recall modal too

Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>