Enable to group pages structure

[kyusupov33]

What problem does this feature solve?

This feature will allow people, which develop in team make their own directory structure. Directory ./pages required contains all vue files and routing it. But developers will be more easy to developing, if they will have - teams or group directory -> team/group name -> pages. Also, each group will contain own store folder.

What does the proposed changes look like?

We can put group names in nuxt.config.js option and then in @nuxt/builder where we generating route add code to check this option. If it not empty, generating custom routes by groups.

Also for store. If we don't create store directory in root, we can check it and pass groups name from options in builder.

_{This feature request is available on Nuxt community (#c8454)}