Day 7! - Sanity.io Headless CMS added

Added Sanity.io headless CMS Configuration

Major issues today with the build. Nothing changed from Day 6.

Sometimes you get issues with windows permissions and nothing that you attempt (yarn cache clean, delete .next, delete node_modules etc., works. The only way is to do all the above and then restart your machine and rebuild/deploy. I think that the CPU is the issue, as I have some idea that when Windows updates, the CPU goes to 100% and bamm! Nothing works. It could also be dropbox or OneDrive. Something happens and all the CPU resources get chewed up.