Support iOS Custom URL Scheme

[qrevel]

Is your feature request related to a problem? Please describe. I'd like to open an iOS navigation application from umap with OSM metadata. For example, opening direction to the nearest train station of a umap feature in Google Maps.

The custom URLs Schemes from Apple applications are currently not exposed through the Popup of a feature. The URL is completely stripped out.

Although Google Maps supports Universal Links, some other apps like navigation app like MagicEarth only supports URL Scheme.

Describe the solution you'd like I believe it comes from the ALLOWED_URI_REGEXP that filters out custom URI. My idea would be to open up that list to support any URI scheme.

Describe alternatives you've considered

Additional context Might be linked to https://github.com/umap-project/umap/issues/1950 in order to have a fully customized HTML editor. The current one is a "purified" version only.