Add ink! dependencies to Playground

[achimcc]

Implement loading of a .json file as part of the FE

This will allow ink! Playground/Rust Analyzer to provide error correction/syntax hightining and auto-completion for ink dependencies/sourcecode.

• [x] Implement loading it Typescript and passing as string to RA

• [ ] Since the file which contains the ink! Dependencies is approx 50mb large (however, only 5mb gzipped), it would be nice to optimize the way in which it is loaded. Possible approaches:

  • Split into chunks
  • Stream the JSON and batch process it