implements #9658
BREAKING CHANGES:
Possibly breaking if a project has a main field set in the nativescript.config.ts - since after this lands, this value will be used instead of package.json main.
The impact is likely very small, the steps to migrate:
(Option A) remove main from nativescript.config.ts if set
(Option B) update main to the correct path in nativescript.config.ts if set incorrectly
* feat: file replacement handling for TS and pure file copy replacements
* test: add tests for replacements & refactor a bit
Co-authored-by: Igor Randjelovic <rigor789@gmail.com>