Selection for which frotend to use in Powder
At some locations, it will be possible (and necessary) for users to be able to select between different RF frontends, such as FDD and TDD. The immediate need is for users to be able to tell us which one they want, so that we can configure things appropriately. Eventually, (according to @alex_orange) it may be necessary to make sure that multiple experiments using incompatible frontend settings cannot run at the same location at the same time.