<!-- Thanks for opening a PR! Your contribution is much appreciated.
To make sure your PR is handled as smoothly as possible we request that
you follow the checklist sections below.
Choose the right checklist for the change(s) that you're making:
## For Contributors
-->
### What?
This PR implements a feature for the turbpack to support (partial)
transform configuration inherited from ts/jsconfigs, notably for the
legacy decorators and jsx runtimes.
### Why?
### How?
- Closes WEB-667
036f540bb4