Prompt for password when running `files_external:scan`

⚠️ This issue respects the following points: ⚠️ • This is not a troubleshooting question, general support matter, or webserver/proxy problem, but likely a bug _(if unsure, ask the [Community Help Forum]( • This issue is not already reported on [Github]( OR solved at the [Community Help Forum]( _(I've searched!)_. • I'm using a maintained major version of Nextcloud Server and tested against the latest patch level. _([Supported major versions and current patch levels]( • I agree to follow Nextcloud's [Code of Conduct]( • I've tried my best to provide clear reproduction steps that someone unfamiliar with this bug could use to reproduce it. Bug description occ files_external:scan does not ask for password on stdin, and there is no option to make it do so, as far as I can tell. This is a potential security risk, because on systems without hardened /proc, a simple ps -au will tell any unprivileged user the password that was passed on the …