Context state management: reduce re-renders.

Our state management paradigm in the Qx Team (former Unity team) has been to use Provider/Context for shared state. A side effect can be un-intended re-renders if we don't use certain patterns.

* provider-induced re-renders:
* see [the three tips starting here](https://www.developerway.com/posts/react-re-renders-guide#part7)
* we currently get around these by pushing the Providers further up the virtual dom tree, resulting in us not taking full advantage of the ability to scope state scope downwards (by pushing the providers further down the virtual dom).
* context selector re-renders.
* see [here](https://www.developerway.com/posts/react-re-renders-guide#part7.4).
* we definitely have are using the "re-render heavy" pattern of this pattern in our codebase.

This issue is a request that we assess and implement changes to improve the performance of our new Qx Builder, shared code, and legacy notebooks.