Support alternate S3 endpoint and credentials

[g-saransh]

Add support for secondary S3 credentials. This will enable cases where the data source and catalog are not co-located. S3 buckets may have different credentials.

[s-akhtar-baig]

@g-saransh, thank you for submitting the issue! Would you like to contribute to the implementation the feature? We can keep the conversation going about the implementation details here.