Add new dynamic component to query editor control or query control dropdown

[jezdez]

To extend 5dd5226 a bit and allow additional features such as the old "Explore in Iodide" button to be available beneath the query editor we should add a new dynamic component to add extra "export" options via Redash frontend extensions.

Since DynamicComponents by design only allow exactly one other component to register against a dynamic component name we may want to create a small wrapper that allows multiple components to register themselves. Of course we should ask upstream if that extension of the DynamicComponent registry to accept many components under a name is in their interest as well.