docs(webpack): add installation instructions

[evenstensberg]

Description of Problem

There's no way of knowing how to bundle vue 3 with webpack 5.

Proposed Solution

Documentation on this

Additional Information

[NataliaTepluhina]

@evenstensberg thank you for the contribution! However, in this section, we only cover Vue-specific tools from our own ecosystem. That's why we don't cover webpack or Parcel builds here, for example.

However, I believe we could add a link to the end of the Vue CLI section (CLI uses webpack under the hood), mentioning that if you prefer to set up the webpack build manually, you can use vue-loader

[evenstensberg]

Could you add that?

[NataliaTepluhina]

@evenstensberg Sure! But I would need to open a different PR because I can't make changed to your forked repository

[skirtles-code]

I've been experimenting with ways of wording this and I think it might make more sense to add a note to the npm section rather than the CLI section. I'm going to ruminate on it a little more but I should have a PR up in the next few days.