Background script logs 'Hello undefined!' if the plugin is installed into a project with Vuex

[siphomateke]

The generated background script logs Hello undefined! instead of Hello bar! if the plugin is installed into a project where the user installed Vuex on project creation.

This is because Vue CLI generates a store.js file and since the background script imports ./store, Webpack imports store.js instead of store/index.js.

[adambullmer]

Decided I'll just go ahead and remove vuex/vue router from the scaffolding to keep things simple, and put out an example repo to show how it can all be put together