Add confirmation for removing a trusted server

⚠️ This issue respects the following points: ⚠️

• This is a bug, not a question or a configuration/webserver/proxy issue.
• This issue is not already reported on Github OR Nextcloud Community Forum (I've searched it).
• Nextcloud Server is up to date. See Maintenance and Release Schedule for supported versions.
• I agree to follow Nextcloud's Code of Conduct.

Bug description

It's really easy to accidentally remove a trusted server especially that the consequences of that mistake can be costly.

Steps to reproduce

1. Go to sharing admin settings
2. scroll to trusted servers
3. click on the delete icon of one of the servers
4. voilà

Expected behavior

There should be a type of confirmation where you should even be prompted to put in your password.
Also when adding, as it sends GDPR user info to others.

Nextcloud Server version

master

Operating system

None

PHP engine version

None

Web server

None

Database engine version

None

Is this bug present after an update or on a fresh install?

None

Are you using the Nextcloud Server Encryption module?

None

What user-backends are you using?

• Default user-backend (database)
• LDAP/ Active Directory
• SSO - SAML
• Other

Configuration report

List of activated Apps

Nextcloud Signing status

Nextcloud Logs

Additional info

No response

Begin in the sharing admin settings and trace the trusted-server add and delete actions from the UI. Define the confirmation and password-prompt behavior for removal, and determine whether adding a server also needs confirmation; the work is done when these actions prevent accidental changes and the relevant tests pass.