Improve template and CLI-related information in the Quick Start

[ikoevska]

From Vladimir Amiorkov via email:

The Quick Start shows how to use the vue CLI which created a very strange “new” {N} app for me. I was not sure what this was supposed to create. It looked like a project that shares the code between VueJS web and {N} Vue, still not sure what the “vue init nativescript-vue/vue-cli-template ” command is creating for me.
Suggestion: It would be great if the documentation about “Quick Start” has a section that describes what the “nativescript-vue/vue-cli-template” template hold. Maybe some of the text from here, or maybe I was expecting too much from the “Quick Start” section but its current state left me wondering in the end.

Tasks:

• Explain what the suggested commands do.
• Provide information about the created template (from a vue and {N} perspective). Could link to a more in-depth template overview.