Make it possible for a marker to link to another marker

Is your feature request related to a problem? Please describe.
It may be a common use case that a marker might relate to other relevant makers. It would be great if a marker's popup could contain links to other markers.

Describe the solution you'd like
Have a standard way to include in a popup links to other markers. The link, once activated, would:

• deactivate its own marker's popup,
• center the map view on the target marker,
• and activate the target marker's popup.

Describe alternatives you've considered
Just referencing the other marker by an id, with no link, but that is confusing, awkward, unwieldy, and impractical for the end user, which not only would have to keep in mind an id but also have to search for it around the map.

Additional context
That would make it possible for users to easily navigate between relevant markers.

However, activating markers by links might not be a feature that leaflet.js itself supports, I haven't checked yet.

The issue names no files or tests; start by examining Folium's marker popup handling and the Leaflet.js marker APIs. Done means a popup link deactivates its current marker, centers the map on the target marker, and opens the target popup.