Replace Base64 with atob/btoa

See Archivematica commit 2f3092c0b9fef0dd177fbe74562592acbe1bc5f5.

Fixes #7698.
Logging: Configure

refs #6812

Configure Django's logging and change references from logging root module
(logging.foo) to the fetched logger. Disable South having logging at
DEBUG.
Duracloud: Add logging
Logging: Add verbose log file, move to /var/log/archivematica

Add verbose log file that logs DEBUG logs as well.  Move logs to
/var/log/archivematiaca - assumes that is writeable.