Support for mountpoint S3 CSI driver to read AWS profiles from a pod level configuration for authentication

[harish-sc]

/feature

Is your feature request related to a problem? Please describe.
Currently, the driver only supports pod-level credentials via IRSA, which limits its compatibility with pods that use different AWS profiles or the Token Vending Machine approach to obtain short-term credentials for accessing AWS services.

Describe the solution you'd like in detail
If the CSI driver could use the AWS profiles configured in the ~/.aws/config file inside the pod for AWS S3 API authentication, it would allow the passing of short-term credentials via the TVM approach, enabling access to different buckets with distinct policies.

For eg., Inside the pod if ~/.aws/config file looks like below,

[profile first-bucket]
credential_process = /token/call-tvm -feature first-bucket
[profile second-bucket]
credential_process = /token/call-tvm -feature second-bucket

This would enable us to specify a profile, similar to how the Mountpoint-S3 CLI allows selecting a profile for credentials, as described in its configuration documentation.

Describe alternatives you've considered
The current alternative is to configure IRSA at the driver level, granting access to all prefixes within an S3 bucket. However, this results in broad access, lacking the fine-grained control needed for multi-tenant systems that enforce prefix-level restrictions and rely on TVM for obtaining short-term credentials to access specific prefixes.

Additional context
We are implementing the approach detailed in this AWS blog to obtain short-term credentials within a pod for accessing AWS services.