Filter functionality

[MirandaEcho]

Confirmed filter functionality:

• Type of organization will be a dropdown/single select.
• Category/tag will be a dropdown, limit of 3 selections, all results much contain all selected terms (AND) so that selecting multiple tags further narrows search results.
• We will also update the no results found message to say something like "please try reducing the number of selected tags to see more results).

[benlk]

Starting a branch for this off of #134; we can decide tomorrow morning whether to merge that or if there's anything else that needs to be done in it.

[benlk]

• - submit the form when the <select> changes
• - track whether the inputs in the details element are changed, and how many are checked
• - when the <details> element is closed or otherwise onBlur, if the inputs there are changed, submit the search
• - limit the number of checked inputs to no more than 3: if it's 3, disable all inputs until one is unchecked
• - add note to bottom or top of details saying it's limited to three