Make PipelineRoot and DefaultBeamArgs provider-specific

[jmendesky]

Overview

The storage location for pipeline artifacts, models, and beam execution files should be configurable per provider.
The same applies to DefaultBeamArgs

Notes

Instead of passing PipelineRoot and DefaultBeamArgs from the controller, the compiler should construct these from the provider configuration.
This would also allow us to no longer pass the ExecutionMode to the compiler as this is already part of the provider configuration.