Remove all instances of "RedHat" from Couchbase documentation - it's two words: "Red Hat"

There are a lot of instances in the documentation where we spell Red Hat as one word "RedHat".

Red Hat are one of our closest partners, and we should try our best to honor their branding. The company should be referred to as "Red Hat", and their products should be referred to as "Red Hat X" (Red Hat Enterprise Linux, Red Hat OpenShift, etc.)

At the very least we should remove these from the upcoming releases of each component. Perhaps we should also remove them from the most current release as well.

Another effort is being done on the .com side of things to change all of the instances there.