Support `valueFromEnv` for `jwkFromUrl` & `issuer` field in `auth-config.yaml` file

[sanchitdikshit]

Component

Graphql Engine (for features that relates to graphql features; metadata modeling) -> c/v3-engine

Is your proposal related to a problem?

jwkFromUrl & issuer field currently do not support valueFromEnv and it only supports the string values in auth-config.yaml file.

Describe the solution you'd like

Ability to use valueFromEnv instead of the hardcoded String

Describe alternatives you've considered

The current workaround is to use separate Supergraphs.

[ashishtilara]

One more request related to this is the documentation on encoding the values and examples for other attributes. for example, I have following setup that works but notice ~1 in path at some places to replace /, without that the parsing doesn't work.

kind: AuthConfig
version: v2
definition:
  mode:
    jwt:
      claimsConfig:
        locations:
          x-hasura-default-role:
            path:
              path: /https:~1~1example.com~1user/context
          x-hasura-allowed-roles:
            literal:
              - ADMIN
              - USER
          x-hasura-user-id:
            path:
              path: /https:~1~1lynksupplychain.com~1user/user_id
              default: null
      tokenLocation:
        type: BearerAuthorization
      key:
        jwkFromUrl: https://auth.example.com/.well-known/jwks.json
      audience:
        - https://api.example.com
      issuer: https://auth.example.com/