Add support for interactive authentication

[pavelzw]

Some people might not want to leak their tokens to their bash history. An interactive authentication mode would be nice.
Maybe something like

$ pixi/rattler-build auth login --interactive conda-token
Host: my.quetz.instance
CondaToken: <token not shown>
Authentication successful.
$ pixi/rattler-build auth login --interactive basic-auth my.artifactory
Username: my-user
Password: <password not shown>
$ pixi/rattler-build auth login --interactive bearer-token
Host: repo.prefix.dev
Token: <token not shown>

[wolfv]

Actually we'd also like to have some integration with our website ala gh auth. But yes, this is also a valid idea!