Improve `configure_esbuild` script and/or add instructions for manual installation to README

[tonydangblog]

Right now the configure_esbuild module is simply copying over the the files from the assets/copy directory and prompts the user if they want to override the files if it already exists. This works for new projects, but for existing projects with existing files, this is not ideal.

A possible solution could be to improve on the script...

• Copy the files if not existing.
• If a file already exists, attempt to inject the new code needed into the existing file.
• If injecting the code fails, show a message to direct the user to a section in the README showing the necessary code changes.

Another solution could be to not have a script at all and just show the user what code needs to be added in the installation instructions. Not a fan of this, but it works. 🙃

In either case, updating the installation instruction with what code changes are needed would be useful so that if the script fails, at least the user knows what needs to be done manually. I can help add this if you think it'd be helpful :)

[woutdp]

An update to the readme would definitely be useful. A section on "manual" installation maybe.

I don't mind the copy functionality that much as I assume if you have a custom setup already, you know what you're doing and you can see in git if it overrides your previous config. You can then manually fix it.

But a manual setup guide might be handy!

[tonydangblog]

Cool. I'll take a look at adding a "manual" installation when I get the chance :)