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.

example.config.yaml

@@ -8,7 +8,7 @@ secrets:
     key: "s3 API key"
     secret: "s3 API secret"
     # use region format like such
-    endpoint_url: "https://{region}.digitaloceanspaces.com"
+    endpoint_url: "https://s3.{region}.amazonaws.com"
     #use bucket, region, and key (key is the archived file path generated when executing) format like such as:
     cdn_url: "https://{bucket}.{region}.cdn.digitaloceanspaces.com/{key}"
     # if private:true S3 urls will not be readable online
@@ -120,4 +120,5 @@ execution:
     screenshot: screenshot
     hash: hash
     wacz: wacz
+    replaywebpage: replaywebpage