Update docs for v1

[voliva]

With the API stabilising for v1, we need to update the docs to match the latest changes.

More importantly, we also need improve the overall structure to make it easy to understand for newcomers.

Some actions that I've gathered from some chats, and some brainstorm:

• Add video of react-rxjs presentation
• Update existing examples using the auto-source$ feature of <Subscribe />
  (where aplicable)
  • Update reference of <Subscribe /> to reflect new changes
• Update reference of utils with the latest changes
  • createSignal/createKeyedSignal
  • split/collect/collectValues deprecated
  • partitionByKey
  • combineKeys
  • getGroupedObservable
  • contextBinder
• Add examples to reference
• Add minimal example in react-rxjs' README.md
  (I think it will make it a bit more visual on first sight)
• Add recipes
  • Capture input
  • Managing lists
  • Load data with paremeters
    (inspired from connectFactoryObservable: Object parameters will cause infinite loops react-rxjs#125)
  • Loading state (leveraging suspense)
  • Manage subscriptions
  • Use case for contextBinder
  • Use case for selfDependant
  • Codesplit
    • Preloading data
  • Testing
• Add FAQ
  • Why isn't there a hook that accepts an observable as a parameter?
    value = useObservable(stream$)
  • I'm getting a "Missing subscription" exception, what's wrong?
  • Why isn't my signal emitting the value I just sent?
    (subscribing late to the signal)

What else am I missing? thoughts? @josepot

[hoclun-rigsep]

Would like to suggest a 'recipe': Redux brags that its state management makes 'undo/redo' easy. Perhaps we should demonstrate that with react-rxjs.