Add support for `add_yield_map` in `ProcessingSteps`

[iyedg]

Feature description

ProcessingSteps currently only supports filter and map. yield_map which would correspond to an add_yield_map call logically would be a good fit here.

Are you a dlt user?

Yes, I use it for fun.

Use case

I would just like to have parity between the declarative and imperative paradigms of the library.

Proposed solution

ProcessingSteps would now accept a yield_map field.

Related issues

No response

[rudolfix]

this will be pretty helpful and in certain cases usage of transformers won't be needed like #3064

[iyedg]

I would be happy to implement this. But looking at the tests, there doesn't seem to be testing targeting the ProcessingSteps logic specifically, any guidance on this will be helpful.

[alkaline-0]

Hey @iyedg Nice to meet you, I'll take a look at the entire ticket and come back to you ASAP then we can see how to proceed forward from there, does this sound good?