Got rid of X86_ONLY and friends in HaikuImage, FloppyBootImage, etc.
Instead we use build feature specification annotated lists with
FFilterByBuildFeatures (either explicitly or implicitly where passing
the list directly to the image rules).
I just translated the variables to the respective annotatation in most
cases, though in some cases different annotation would be more correct
(e.g. for the OpenGL stuff).
Provides a simple framework for addressing #3798. The interested reader
may add the build features and add/adjust the annotations accordingly.
