Cleanup redirect rules for Qt for MCUs doc

Qt for MCUs has at least three active documentation sets at any given point. In addition, the older sets are in the archive. Currently we use redirect rules to make sure the latest version is served, unless the query is for an archived version. All the other documentation sets on doc.qt.io, organize the different docsets with version suffix in their name, making it easier to find the latest set without the need for redirecting, at least in most cases.

The Qt for MCUs docsets should also follow the same directory structure and drop/reduce the redirect rules.