Implemented file upload progress to the frontend using XMLHttpRequests,
since fetch() doesn't offer this functionality right now. Bit of a
fragmented approach to requests in the codebase right now, but hope to
resolve this soon. Not styled at all either.
Also added some nifty commands to the Makefile for producing smaller
binaries using some compiler flags and upx, and requires upx to be
installed (make small and make small_pi).
Reworked the fileprovider to proxy data directly from the provider
rather than attempt to funkily redirect when needed, since it was overly
complex and wouldn't work well in the long run. Temporarily added "file"
as constant return for determining the filetype through Backblaze.
Added a Makefile to make life easier as well, and rewrote the README to
reflect the refactor/rewrite and new approach to providers.
