[Feat]: Fine-grained expiry for JWT Bearer access entries

[matheuscscp]

Is your feature request related to a problem? Please describe.

Hi 👋 !

I was looking at the Distribution spec: https://distribution.github.io/distribution/spec/auth/jwt/

    "access": [
        {
            "type": "repository",
            "name": "samalba/my-app",
            "actions": [
                "pull",
                "push"
            ]
        }
    ]

It would be awesome if Zot supported an exp claim per access entry, i.e.:

    "access": [
        {
            "exp": 1415387315,
            "type": "repository",
            "name": "samalba/my-app",
            "actions": [
                "pull",
                "push"
            ]
        }
    ]

My use case is: I want to build enterprise licenses for my org's products on top of OCI JWTs. If Zot supported an exp claim per access entry I would be able to issue licenses containing multiple products at the same time that are mapped to OCI repositories. A customer could have a contract-long product and a free-trial one in the same license.

Describe the solution you'd like

When access is evaluated based on the JWT claims, the access entry is discard if the expiration has passed.