Change typescript files for build

[nicollite]

Description

Change tsconfig file for build the sorce code in typescript into js and add config for later testing with with jest directly in ts. Also change package.json to get the compiled files with "main" and "types" to get the typescript interfaces and types

[joshpensky]

Hey @nicollite 👋 Thank you so much for submitting these changes!

Unfortunately, we're not accepting PRs for this branch. We are currently revisiting TypeScript support for firestore-jest-mock internally and this branch was just an initial test for the switch.

We hope to have more information soon, but until then keep your eyes out!

[nicollite]

Hey @joshpensky in this time I was working on a wider firestore mock using typescript, for now I'm in the testing fase and I want to submmit the code for review, should I take a new branch, beacause It differ a lot from the code you have now?

[joshpensky]

@nicollite Since our work on the migration is currently in progress, we would recommend continuing your work in a new branch!