Link to specific FAQ from donation form (checks)

* Adds slug to FAQ model
* Uses this slug when generating anchor links on the FAQ page
* Updated fixtures to include latest FAQ content (and slugs)
* Non-JS users get all FAQs open by default
* If a url hash is present, it is checked when initializing the collapsibles. If there's a match, that collapsible stays open
* Link to the specific question from the donation form
I will check with Nick to see if the "collapsible" part is important for aria. It was actually something I found when learning about aria, not something I made up myself.