use `@whatwg-node/fetch` and remove all other clients

[saihaj]

Today we are using axios, isomorphic-fetch and even built in fetch. We should refactor all these and utilize @whatwg-node/fetch for consistency. In graph-tooling we create a wrapper around @whatwg-node/fetch and provide a shared headers which is a good practice.

You can learn here why use @whatwg-node/fetch