Replace subscriptions-transport-ws with graphql-ws

[carrolp]

The subscriptions-transport-ws dependency is deprecated and the readme recommends switching to graphql-ws: https://www.npmjs.com/package/subscriptions-transport-ws

However, as noted in https://www.apollographql.com/docs/apollo-server/data/subscriptions/#switching-from-subscriptions-transport-ws:

If you use subscriptions with Apollo Client you must ensure both your client and server subscription protocols are consistent for the subscription library you're using.

I.e. the Razeedash-api server and ClusterSubscription client must be using the same library. To transition to graphql-ws will likely require updating ClusterSubscription to tolerate websocket failure and instead rely on polling until the server is updated later, after a period of transition.