warn by showing message in the top panel when scrolling far away from place where edits were made

Description

Current situation:

• be clueless newbie (this is normal, fine and welcome!)
• made an edit (even more welcome)
• pan across ocean
• made edits there
• create globe-spanning bounding box (not really welcome)

See https://www.openstreetmap.org/changeset/111425950 as an example

Proposal:

• when there active edits and one is far away from their bounding box show a warning message in top menu

Banner like #8727 can be used to show message "please, save before making other edits far away"

Or something pointing to save button (crude mockup below)

This is intended to be a specific subproject solving #8590 partially or fully