convert URLs in popup content to links

[emyl3]

What

This PR converts URLs in the content of the popup to clickable links. This PR does this for the "Seeking Volunteers" and "Notes" section.

Why

This PR resolves #134

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

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

Check the app in the following web browsers:

• [X] Chrome
• [X] Firefox
• [ ] Edge
• [X] Safari