Support external password managers

Some users have an external password manager, such as Dashlane or Bitwarden which they want to use to synchronise their passwords between their devices.

Andoid offers the Autofill framework so anyone can implement an app that can be used as a "password manager provider". Apple does so as well on iDevices.

It would be awesome if there was a standardised way to support external password managers on desktop (and mobile, with Purism's phosh).

The simplest way to do it in my opinion would be to define a standard around a DBus service. Password managers providers (e.g. Dashlane, or even GNOME Password Safe) would provide the DBus service, and Web would be a client to that service.

My technical knowledge of the GNOME ecosystem is pretty limited, but I'd be more than happy to assist with the use cases.