Add browsertrix profile config option

This commit adds a browsertrix profile option to the configuration. In
order to not require the passing of the browsertrix config to every
Archiver, the Archiver constructors (include the base) were modified to
accept a Storage and Config instance. Some of the constructors them pick
out the pieces they need from the Config, in addition to calling the
parent constructor. In order to avoid a circular import that this
created the Config object now defines the default hash function to use,
rather than having it be a static property of the Archiver class.

utils/gworksheet.py

@@ -21,7 +21,8 @@ class GWorksheet:
         'duration': 'duration',
         'screenshot': 'screenshot',
         'hash': 'hash',
-        'wacz': 'wacz'
+        'wacz': 'wacz',
+        'replaywebpage': 'replaywebpage',
     }
 
     def __init__(self, worksheet, columns=COLUMN_NAMES, header_row=1):