Remove build flags with default values

[pmeinhardt]

~Only apply build optimizations for creating releases or if specifically requested. This roughly cuts build times in half for development builds.~

Remove webpack build flags that were using the defaults.

[pmeinhardt]

looks good, is this disabling code ~obfuscation~ minifaction for dev builds? Would make debugging the extension much easier

Thanks for asking about it.

I double-checked the documentation and it turns out, 'production' is actually the default mode. I tried again and removing/re-adding the flag doesn't make a difference. 🤦‍♂️

I'll check again later, to see whether setting --mode=development instead makes a difference.

[pmeinhardt]

Here's a link to the docs for reference: https://webpack.js.org/configuration/mode/