add custom dungeon links like you can add customer city links

[TachyonicSpace]

i noticed you can edit the cities from their link and add the custom url to them, i think adding that to the dungeons as well would be nice.

[Azgaar]

Hello, dungeon links are editable via the Notes Editor.

Steps:

1. Click on a dungeon marker
2. Click 'Edit place legend' button (the first one) in the dialog
3. Click on the first button 'Source code'
4. Change the iframe src