Clean up the mess we have with the various repositories

We need to do some clean-up for our helper tools and scripts. Currently those are located in someone's personal repo, in qtsdk, in tqtc-qtsdk, in qtrepotools. We need to create a list which ones are actually used, where those should be located etc and finally do the actual clean-up.

By default most of those should be in qtrepotools because from there everyone has access to them.