WIP: Support pages

I've removed most of the styling changes and raw HTML that existed on !51 (closed), !52 (closed), !53 (closed), !54 (closed).

I have used raw HTML and custom styling in the messenger comparison table so that it can be responsive on smaller screens and not overflow the page.

I've kept the "how it works" page separate from the FAQs, but still kept it under the Support folder. I also added a dropdown menu to make the Support page links available. Some CSS has been added for the dropdown menu styling and to make it responsive.