💈 v.0.15.1 New documentation adds and updates

We're expanding the use of the Vitepress static site generator. It's soon reaching it's v.1.0 and the team adds so many great improvements that Gun-Vue is becoming better just by bumping the deps. But we can utilize that new power more properly. It's best use is the documentation. And it's and art in itself.

We're guided by the Diataxis documentation framework, that establishes 4 main sections: Tutorials, How-to's, Reference and Explanations. Let's try to keep that in mind and build up all this content.