Consider memoizing Auth0context functions

[zdila]

Currently functions references of Auth0Context.Provider are changed everytime when <Auth0Provider> renders. In that case it makes useAuth0() to return different function references and then, if they are later used in dependency arrays for other hooks (eg. useEffect), they cause them to reevaluate.

From what I see it should be safe to exclude those functions from dependencies of other hooks, but react-hooks eslint rules will still complain.

Introducing useCallback for all functions of the context value in auth0-provider.tsx should fix this.

[adamjmcgrath]

Het @zdila - thanks for your suggestion

I'll add something to our backlog to investigate this