Addressing a bug where the configuration would try to interpret the
provider name from the entry in the configuration, rather than the
explicit `provider`. Also removed background uploading from Backblaze
(was worth a shot).
Implemented a much-needed Setup() function for providers to implement,
which (as demonstrated in the backblaze provider) allows for
authentication in advance of needing to make calls to remote locations.
This could also be used to create a directory or perform some other
sanity check required for the provider to work. So far, haven't noticed
any performance impacts from this approach, besides not needing to auth
each time we make a request.