[FEAT] - react context wrapper

[DanCouper]

Which package is this related to?

Specify the package, or if it is a new package suggest a name.

If this covers multiple packages, if possible open an issue for both and PR separately: this will keep the PR's scope as small as possible (plus each package needs separate version bumps & republishing after the fix has been applied).

• [ ] @thingco/auth-flows
• [ ] @thingco/graphviz
• [ ] @thingco/react-component-library
• [ ] @thingco/shared-types
• [ ] @thingco/unit-formatter
• [ ] @thingco/user-preferences
• [ ] @thingco/user-preferences-store-web
• [ ] @thingco/user-preferences-store-native
• [x] new package (@thingco/react-context)

Is your feature request related to a problem? Please describe. Creating a context provider involves this pattern over and over and over again:

• use createContext to create the context, with a type that is either the value or null. Create it with null.
• write a provider component using Context.Provider that takes in some values as props and stores them in the context.
• write a hook that wraps useContext and errors if context is undefined

Describe the solution you'd like

• a createContext wrapper that returns [Provider, useProvider]
• this has prior art -- see https://github.com/radix-ui/primitives/tree/b324ec2d7ddf13a2a115cb5b11478e24d2f45b87/packages/react/context -- that works, but need to be a bit smarter about the value, as the context providers often do {something} with the props to instantiate the value before storing it.