Packaging: Improve source map and browser usage for external bundlers

[jasonpaulos]

While working on https://github.com/jasonpaulos/decipher-22-pyteal-talk, I became aware of a few deficiencies of using this SDK in React. This PR attempts to improve most, but not all, of the issues I encountered. They are:

• Missing sources: while we generate and ship source maps with our package, we don't include the actual sources, which make the source maps essentially useless since they have nothing to map to. To fix this, I've included the src directory in our release bundle.
  • As an additional improvement that wasn't strictly necessary, I moved the index.ts file into the src directory. This helps simplify the directory structure for our sources and compiled code. As far as I'm aware there's no downside to doing this.
• Failing to import the crypto module: as I explained in this comment, our dependency tweetnacl-js attempts to import the crypto module in all environments to see if it's available, but that module is not necessary in the browser. Due to the strict nature of bundlers, this commonly caused an error. However, by modifying the browser field in our package.json, we can declare that that module should be ignored by browser bundlers.
  • Note that tweetnacl-js also does this, which I thought would be sufficient, but for some reason is not.
• Building on Node v18: our version of webpack has a bug that prevents it from building on newer versions of node, so I updated it.
  • While I was updating packages I also updated chromedriver, but this isn't strictly necessary.

The other issue I found but is not addressed in this PR is with regard to Buffer, and I've described that more in #708.

[algochoi]

Looks like good improvements:

As an additional improvement that wasn't strictly necessary, I moved the index.ts file into the src directory. This helps simplify the directory structure for our sources and compiled code.

Just checking since the PR makes changes to local paths: this won't affect how external users use the module correct?

[jasonpaulos]

That's correct, the path changes will not affect what's exposed to users. The files referenced from our package.json are unchanged.

[algochoi]

LGTM 🚢