have NSS support clientId & clientSecret based authentication

[bourgeoa]

[ThisIsMissEm]

So currently NSS only supports dynamic client registration, which means in order to access data in a pod, you need to do the complete login flow, which is sufficiently complex. For the Node.js tests on the Inrupt SDKs, we tend to prefer using static client registration: https://github.com/inrupt/solid-client-js/blob/main/.github/workflows/e2e-node.yml#L43-L44

The reason for this is that it makes the end to end test code a lot simpler: https://docs.inrupt.com/developer-tools/javascript/client-libraries/tutorial/authenticate-nodejs/#node-js-script-single-user-script

We don't have to interact with a server, as we already have a client, so we don't need to test the dynamic registration, which would require interacting with a browser and running a server.