Make the SerializedDAG & SerializedBaseOp be independent of Task SDK's DAG & BaseOP #52141
Description
Currently, models.BaseOperator and models.DAG use the Task SDK classes.
This was done to maintain backwards-compat and to get 3.0 in a timely manner.
However, we don't want to depend on Task SDK in the Scheduler or the API-server (airflow-core package) - at least not a required dependency.
We only need to ensure we have enough information for the Scheduler & API-server for a DAG & the Operator. This is done via the SerializedDAG & SerializedBaseOp.
So this task involves: figuring out how we can consolidate: SerializedDAG, models.DAG by not inheriting Task SDK; and same for SerializedBaseOp and models.BaseOperator
To do (not ordered by dependency):
- Timetables
- Asset
- DagNode
- NOTSET and ArgNotSet
- DeadlineAlert (and releted things?)
- BaseOperatorLink
- ExpandInput