admin - app instantiation cleanup

Cleaned up how domain, partition and https_domain get set and are stored
(locally) for easy retrieval.  Much cleaner and more reliable than
earlier guesswork. All three of these vars are necessary for a good user
experience.
admin - remove 'beta' from some new interfaces

On setup page, the pages that are functional (shipping, payment,
projects and rss) had the links to the old interfaces removed.  Taxes
and Company aren't complete yet, so their beta tags were left as a
reminder to finish them.
admin syndication - amazon mws