Manual index authentication mode with (or without) keyring

[marcellszekrenyes]

Summary

At the moment I see a two ways of HTTPS authentication for private package registries. Either by storing the username/password/token somewhere, or by directly including it in the URL. My idea/request is to have a mode where the user gets prompted for username/password instead. I have looked around a bit, I can see a few possible options to achieve this and I would be willing to work on such a feature if there is no specific reason not to have such a functionality.

Some possible options that seem to be feasible:

1. Use the --keyring-provider subprocess flag and have a special value for username or username:password combination, which leads to prompts for the credentials instead of using the keyring. (This seems to be the easiest way, but might not be the cleanest option)
2. Create a --keyring-provider manual-input option that then achieves the same.
3. Extending this issue: Add an authentication mode to [index] configuration #11600 with a manual-input mode which then leads to the user being prompted for credentials.

Example

No response