Reinterpret nextcloud internal links

ENHANCEMENT

It'd be nice if the app detected links to the same nextcloud instance: i.e. to a file or directory https://yourservercloud.tld/f/00000000 or to any other subdirectory (essentiallyNEXTCLOUDURL/.*) and redirected to them instead of embedding the result.

Actual behaviour

If an embedded website contains such a link and the user accesses it, there'll be a child Nextcloud GUI instance inside the parent Nextcloud instance, which is confusing, makes little sense and can be repeated indefinitely.

Expected behaviour

Any link inside the iframe which targets the current nextcloud instance causes the parent website to redirect to that URL.

Usage case in which

Embedding the URL of an app running on a subdomain which saves its files inside a nextcloud-shared directory and has a link to the share to find it easier. External, private apps which use nextcloud as a backend.

Start by locating the JavaScript entry point that embeds the external site and handles iframe navigation. Reproduce the nested Nextcloud link case described in the issue, then verify that links matching the current Nextcloud URL redirect the parent rather than embedding another instance.