Locally develop/test any model in sqlmesh

[ryscheng]

What is it?

In a future, where every model has a playground dataset that is loaded into a local duckdb, which powers my dev sqlmesh instance,
I'd like the ability to easily write a model anywhere in the pipeline and test it locally.

[ryscheng]

I should also be able to easily query the playground dataset for any sqlmesh model in existence in our monorepo.