Enhance entry.py to allow for an additional package.json

[leeuwe]

Is your feature request related to a problem? Please describe.
It would be useful for robot-framework-browser-extensions if rfbrowser init would allow for an additional path to a package.json used by the browser extensions. That would make that the node packages will all live in the same location, which I think is preferable. It would also ease the use of extensions

Describe the solution you'd like
I'd like something like

def _rfbrowser_init(skip_browser_install: bool, file: str):

usage:
rfbrowser init skip_browser_install file="path/to/extensions/package.json"

Describe alternatives you've considered
Alternatives are folks having to manually install and debug the package installation themselves and you're likely to end up with multiple node-modules folders in your project, which I consider undesirable.

[aaltat]

@allcontributors please add @leeuwe for ideas

[allcontributors]

@aaltat

I've put up a pull request to add @leeuwe! 🎉

[mkorpela]

@leeuwe could you explain more about what problems you have now with the package linking?

I was thinking that we might also maybe get some help from https://docs.npmjs.com/cli/v7/using-npm/workspaces

[leeuwe]

For example: npm @axe-core/playwright requires obviously playwright, what we already have installed for Browser library.

Npm doesn't handle this very well if it's in a different folder, and I don't like playwright to be installed twice