fix(instantsearch.js): fix user token not being set in time for the first query

[shaejaz]

FX-2955

Summary Double queries happen when the state of instantsearch and insights no longer matches at the time of the first query on page load.

• The search-insights onUserTokenChange and onAuthenticatedUserTokenChange callbacks are not able to set the user-token by the time the first search query is sent. When the user-token is changed by these callbacks, the state has changed from the first query. If a new query is scheduled after this(for example with dynamic widgets), the cache misses due to the changed state and second query is made.

• When useCookie is set to true, insights needs to create a anonymous token and save it as a cookie. Instantsearch would have the token updated with the callback from before, but this does not happen in time for the first query. So anonymous token generation and saving in cookies is now also handled by instantsearch.

• The insights queue is now being access in the middleware's started function to make sure any token set before instantsearch was started are part of the state by the time the first query is made.

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example-react-instantsearch-next-routing-example	Configuration
example-vue-instantsearch-getting-started	Configuration