Add typescript support Part III - Modify Generators to output TS files

[jho406]

This is in the same vein as https://github.com/thoughtbot/superglue/issues/43 . When moving to typescript, we also want to update the generators to output ts files.

Thoughts:

The generators are located in this folder. There are a total of 4 files there that needs to be converted (edit.js, index.js, new.js, show.js).