[ObjectAPI] support asynchronous root resolution

[larkin]

Based on a discussion in chat with @akhenry and @VWoeltjen...

It was previously possible to decorate the model service and dynamically and asynchronously change the root model composition on first load of the application.

We should support this use case in a developer friendly manner that allows multiple plugins to work together to define roots, instead of requiring them to hijack the functionality of other plugins.

In order to do this, will change a few things:

• Will move the default root "mine" to a standalone bundle and disable it by default.
• will implement some method of asynchronously loading roots (either RootProvider or addRoot(function-> promise[roots])).
• some question as to how roots are ordered, may point to RootProvider being a better option as it allows for future expansion.

@VWoeltjen @akhenry feel free to log extra comments here.