Bug 32097: Consistent classes for primary buttons: Lists

Bug 32097: Consistent classes for primary buttons: Lists

This patch makes changes the button markup in lists templates so that
all submit buttons and any buttons that should should be styled as
primary buttons have the Bootstrap class "btn btn-primary."

To test, apply the patch and view lists pages to confirm that everything
looks correct. In most cases there are no visible changes.

Signed-off-by: David Nind <david@davidnind.com>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>