CDK: Create a generic method for transforming records fields in accordance with streams schemas

[Zirochkaa]

Tell us about the problem you're trying to solve

Right now we have few issues where fields types in records don't match types from streams schemas (#4292, #4841, #4827).

Describe the solution you’d like

It would be nice to have a generic solution, a function or a class (like Transformer class in singer), which will go through each field in records (through nested fields too) and transform types to the ones in streams schemas.

Describe the alternative you’ve considered or used

Right now if we want to change type of fields in records we are using transform() function (like in source-github). In this case we need to manually specify fields and desired types. It works good for root keys, but for nested keys it's not so convenient to use such method.

Additional context

First edition of this task will be implemented in #4827 issue.

Are you willing to submit a PR?

Yes

[Zirochkaa]

Blocked on #4827.

[keu]

@Zirochkaa how is this issue blocked by #4827 ?

[Zirochkaa]

@keu we decided to do the first test version of this generic method in Facebook Marketing source in terms of #4827 issue, so this means that I need to add generic function to Facebook Marketing source first, merge it and only then I can move that generic function to CDk (maybe add some improvements).

[keu]

ok, lets call it playground