[FEATURE] Shims or type stubs for pyspark.databricks

[tigerhawkvok]

Problem Statement
When developing locally, an import to pyspark.databricks doesn't have type hints or code completion

Proposed Solution
type stubs -- ideally ones that redirect to the real pyspark.databricks functions -- would be very helpful.

So databricks.sdk.pyspark_databricks would (recursively) shim access to members of pyspark.databricks.

It means something like

from databricks.sdk.pyspark_databricks.sql import functions as dbf

and

from pyspark.databricks.sql import functions as dbf

would be identical, except the former would provide hints locally whereas the latter does not.