Set up credentials provider

[DenisaCG]

Set up the settings credentials provider for the extension and connect the secret inputs to the SecretsManager from jupyter-secrets-manager.

The credentials can be set by accessing Settings -> Settings Editor -> Credentials Provider and include the bucket name, region and endpoint, as well as an optional path to a directory within the bucket to act as root. The accessKeyID and secretAccessKey are considered secret fields and their inputs are connected to the SecretsManager from jupyter-secrets-manager.

Any changes made to the credentials are automatically saved and the drive file browser is updated, the update can take a few seconds to be visible. Every time a field is changed, a new Drive is instated with the new credentials. As the secret fields are not saved, when instating the Drive we fetch the secret values using the provided secret token.

The authFileBrowser plugin was updated to connect to the credentials provider settings. Currently, it first tries to fetch the settings and if they exist the factory returns them, otherwise it looks for the process.env environment variables, which can be used with the development version.

[DenisaCG]

Hey @afshin, do you mind taking a look over the PR? Thanks!

[afshin]

Thank you! This looks good.

I think longer term we should have a discussion about the interaction between settings and secrets and how to minimize the risks involved in storing secrets, but that's outside the scope of this PR.

[DenisaCG]

Thank you for the review! And I agree about a follow-up discussion on the secrets stored from the settings.