Refactor dagster_defs

[damonbayer]

In #1213, we are planning to add ~4 more model assets to our production workflow. https://github.com/CDCgov/cfa-stf-routine-forecasting/blob/main/src/cfa/stf/routine/dagster_defs.py is already quite long.

I think there are opportunities to split it up to make it easier to work with and also to take advantage newer developments in https://github.com/CDCgov/cfa-dagster, say by not having the redundant https://github.com/CDCgov/cfa-stf-routine-forecasting/blob/main/dagster_defs.py file.

One idea for simplification is that the dagster assets for each model might be better defined in the respective model folders in src/cfa/stf/routine.

[jkislin]

One idea I've always had is to have assets in their own definitions file, executors in another, schedules in yet another. Additionally, the dagster docs specify a default schema. I'll take a look and consider all of these options.

[jkislin]

#1289

There are many ways we can do this - any feedback on direction is appreciated.

I find the recommended structures to be quite convoluted. I'm going with something in between what they recommend and what we had with dagster_defs.py

• each "concept" gets its own .py - e.g. assets.py, automaton.py, execution.py, etc.