Bug 31770: Add page-section class to rotating collections page

Bug 31770: Add page-section class to rotating collections page

To test:
1. Apply patch
2. Go to the rotating collections page. Tools / Rotating collections
3. Add some new collections
4. Note that the page looks good with the new page section div.

Note:
I made some indentation changes and fixed a small typo where the 'dropdown-toggle' class was not being properly applied.

Signed-off-by: David Nind <david@davidnind.com>
Signed-off-by: Katrin Fischer <katrin.fischer@bsz-bw.de>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>