unify root executables behavior

[ewerybody]

While working on the build scripts to support the new ahk2 stuff and incorporating the root executable generation into the python script part I ended up having the executables in the build root directory and not in the new a2 package. While being at it I just tested what these where doing there and both a2- and a2ui-starter complain 👍 but in completely different ways. The uninstaller pops like all is fine. It should also complain if things aren't where they're supposed to be.