Move to Esbuild bundler.

[samyakkkk]

This PR enables bundling our extension using Esbuild which combines all js files into a single big extension.ts hence reducing our compiled extension size from 14.5MB -> 934KB. 🙌🏼

To note, ESbuild now will also bundle our debug and test builds instead of tsc. So please test the PR once on your system, by

1. Running Extension
2. Running Tests
3. Making sure changes made in the code reflect in the extension.

You will also be prompted to install esbuild Problem Matchers by Connor Peet, it is recommended to install it.

Vscode Documentation on bundling: https://code.visualstudio.com/api/working-with-extensions/bundling-extension#using-esbuild

[wadhia-yash]

You might have to restart your VS code after installing esbuild Problem Matchers. After this it works as expected

[samyakkkk]

Ok @wadhia-yash, thanks for the confirmation.

I'm merging the PR.