[RFC] Add declarative components

[ramiel]

It would be useful to have declarative components. Those components:

• Define a route entrypoint
• Show any children if the current route matches
• Accept, as props, anything a regular route would accept

Possible implementation

A component like that would be something similar to this

<RouterProvider>
   <RouteMatch path="/">
      <ChildComponent />
   </RouteMatch>

   <RouteMatch path="/user/:id">
      {
        (req, ctx) => <ChildComponent id={req.params.id} />
      }
   </RouteMatch>
</RouterProvider>

Question: should the children receive the req, ctx tuple or simply the parameters?

<RouteMatch path="/user/:id">
      {
        (props) => <ChildComponent id={props.id} />
      }
</RouteMatch>

A good reference could be the @reach/router Match implementation.