[Documentation] Would be nice to have a doc showing adding vuetify to an existing vue 3 app without using 'create vuetify'

[JasonGoemaat]

Problem to solve

The steps to add vuetify to a bare project would be nice. The 'create vuetify' creates a plugins directory with three files and it's a little confusing about what it's doing. For an example it would be helpful just to show the code in main.js that is in the sample app creating with 'create vuetify'.

Proposed solution

Add bare-bones info to documentation on adding vuetify 3 to a project created with vite.