Allow users to provide their token via a stdin prompt

[frectonz]

Forum discussion: https://forum.exercism.org/t/allow-users-to-provide-their-token-via-a-stdin-prompt/12492

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Currently the only way to provide a token is via the CLI arg --token. This is not ideal because the token will be saved to the shell history, which makes it easier to steal and easier to leak.

Instead this PR provides an implementation where the user can run the command exercism configure without providing a token and then the user will be asked to provide the token via a stdin input.

This token has been reset.

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Also thank you for making exercism, it is my go to spot for learning new languages.

[github-actions]

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