Shorten the expiry window for the work queue SAS URLs assigned at node registration (#416)

The underlying impact is that nodes must re-register on a more frequent basis.

Nodes find out they are out-of-date is during registration and immediately prior to starting a new set of work.  Requiring nodes re-register on a shortened cycle provides more opportunities for nodes to get re-imaged.

Additionally, this addresses an issue handling the SAS URL expiry in a more clean fashion in the supervisor.

src/api-service/__app__/onefuzzlib/azure/queue.py

@@ -48,11 +48,12 @@ def get_queue_sas(
     add: bool = False,
     update: bool = False,
     process: bool = False,
+    duration: datetime.timedelta = datetime.timedelta(days=30),
 ) -> str:
     account_id = get_primary_account(storage_type)
     logging.debug("getting queue sas %s (account_id: %s)", queue, account_id)
     name, key = get_storage_account_name_key(account_id)
-    expiry = datetime.datetime.utcnow() + datetime.timedelta(days=30)
+    expiry = datetime.datetime.utcnow() + duration
 
     token = generate_queue_sas(
         name,