[WIP] Remove dependency on webpack rails

[samtgarson]

⚠️ Work in progress... ⚠️

This PR aims to:

• Remove dependency on WebpackRails gem to leave the webpack integration up to the end user (to enable usage of Webpacker gem),
• Remove bundled renderer to use this dedicated renderer,
• Make generator optional and only add what webpacker needs on top of it's Vue setup for server side rendering,

[scottcorgan]

@samtgarson how complete is this PR? I'd like to start testing in a production app with Webpacker, but not sure where this PR is at yet.

[samtgarson]

@scottcorgan it's not there yet, but you can use this gem with webpacker as is if you're willing to do some work —don't run the generator and init your app with --webpack=vue. As you're not using the generator you'll have to Bring Your Own Renderer, you can use the one linked to in this PR. You'll also need to write an extra webpack config for SSR and a server entrypoint (like this one). I haven't tested this so YMMV

Unfortunately I'm pretty busy with the day job at the moment but I'll try and get this done in the next week or so.

[t56k]

@samtgarson Any update on this?