Add GCP and OCI file content authentication

[1solomonwakhungu]

What?

• Add ability to pass the content of the credentials instead of local files for GCP and OCI auth.
• Add additional parameters for the user to pass the credential content.

Why?

• Users might need to store the credentials in a remote storage instead of their local machines, this feature would allow users to store their GCP and OCI credentials in a remote storage, but able to reference the content of the file credentials.
• Adding the additional parameters allows the user to either pass the local file name or the content of the credentials file. If a user passes both the local file name and the content of the credentials, the content of the credentials file will take precedence and be used during authentication.

Testing

• Tested passing the OCI credentials.
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• Tested passing the GCP credentials.
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• Tested passing no OCI and GCP credentials.
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