Improve modularity of Hawtio Core for better embedding of it into a custom console

[tadayosi]

Improve modularity of hawtio-react so that it becomes easier for the dynamic plugin (and other applications) to embed its components.

• https://github.com/hawtio/hawtio-online-console-plugin

[tadayosi]

It doesn't seem to be high priority right now.