Very messy working draft of filters, semi-broken draft of sorting

[amaxama]

What

Brief description of changes.

Why

What problem does this pull requests solve? Reference related issues if appropriate.

Ensure the following interactions work as expected. Please test using a mobile form factor.

• Tapping on a marker on the map displays information about the marker in a popup.
• Tapping the "Show list of locations" button replaces the map view with a list view.
• Tapping an item in the list replaces the list view with a map view, and navigates the map to the tapped item on the map.
• Tapping one of the ✅'s in the legend filters items on the map and in the list.
• Changing the language to spanish changes things on the page.
• Clicking the Help/Info button opens and closes a menu with information.
• Clicking the X Close button on the Help/Info screen closes the modal.

Check the app in the following web browsers:

• Chrome
• Firefox
• Edge
• Safari