[Browser] Improve TreeShaking approach for webpack

[claytonneal]

Objective is to review the output webpack js file size for browser users
This could be optimised by looking at how TreeShaking works and what exports we have
Ideally if a browser app is just doing minimal operations, the output js file should be small

[leszek-vechain]

This is webpack approach to tree shaking, not sure if we are using it:

https://webpack.js.org/guides/tree-shaking/

There is a couple of options we can set there.

[leszek-vechain]

Added config for tsup to use rollup optimisations plus minify (esbuild is using tree shake by defult too)