[Docs] Added archives/extensions + added introduction
[Docs] Added archives/extensions + added introduction

pkarw/vue-storefront,pkarw/vue-storefront,DivanteLtd/vue-storefront,DivanteLtd/vue-storefront,pkarw/vue-storefront,DivanteLtd/vue-storefront,pkarw/vue-storefront,DivanteLtd/vue-storefront