Set up GitHub Pages and update the About section

[arnaucasau]

Instructions

The project now has the documentation deployed in a branch called gh-pages, but we need to set up the repo to use GitHub Pages by following the next 5 steps. Once the GitHub Pages is set up please update the repo's About section to display the new link.

1. Navigate to your site's repository
2. Click Settings
3. Go to Pages
4. Select Deploy from a branch, under the Source section on Build and deployment
5. Select the gh-pages branch and the / (root) folder in the Branch section on Build and deployment

The default URL where you can find your site is https://qiskit.github.io/qiskit-neko

For further information, you can see the GitHub Pages Quickstart and Qiskit/ecosystem#578.

[jakelishman]

I've just set up things up for GH pages, but I was just on my phone so let me know if I missed something.

[Eric-Arellano]

Looks great. Thanks! We'll set up redirects from qiskit.org.