[Canvas] Allow Rendering of By Value Embeddables

[crob611]

The current Embeddable Renderer expects an Id on its input that it will use to load a saved object by id. This won't work for rendering embeddables byValue. The renderer should be updated to just pass in the config to factory.create instead of calling createFromSavedObject.

This renderer should be pulled out of Canvas and registered as it's own expression_embeddable plugin that can live in src instead of in x-pack.

[elasticmachine]

Pinging @elastic/kibana-presentation (Team:Presentation)