Add urql live query

[jmatsushita]

Adding @live queries in the style of https://github.com/n1ru4l/graphql-live-query

• Stacked on Updated directives PR  #114
• Implemented in liveQuery in the Urql client
• This adds a number of JS dependencies

{
  "dependencies": {
    "@n1ru4l/graphql-live-query": "^0.10.0",
    "@n1ru4l/graphql-live-query-patch-jsondiffpatch": "^0.8.0",
    "@n1ru4l/push-pull-async-iterable-iterator": "^3.2.0",
    "@repeaterjs/repeater": "^3.0.4",
    "@urql/core": "^3.1.1",
    "eventsource": "^2.0.2",
    "graphql": "^16.6.0",
    "graphql-ws": "^5.11.3",
    "isomorphic-unfetch": "^4.0.2"
  }
}

• Testing end to end with a graphql-yoga server with live queries enabled.
• Also refactored the default query_ client to be in the Affjax.Node module to avoid depending on urql across tests.

Example (from the end to end test):

main :: Effect Unit
main = do

  client :: Client UrqlLiveQueryClient Directives Query _ _ <-
    createLiveQueryClient
      { url: "http://localhost:4000/graphql"
      , headers: [ ]
      }

  let
    event = liveQuery client "" $ live {} { greetings }

  handle <-
    HS.subscribe event \e -> do
      log "Live Query update received"
      logShow e

  launchAff_ do
    delay $ Milliseconds (3.0 * 1000.0)
    liftEffect $ HS.unsubscribe handle

[jmatsushita]

@roryc89 I realised I had this PR stowed away jmatsushita#1 as a follow up to the directives one

It'll need some work I think to merge, but wanted at least to make you aware of it, and let you take a look at it before putting more work.