Add a configurable timeout around backend live feed startup

For now make it a larger value but ideally in the long run we can tune
it to specific backends and expose it in the config(s).

piker/data/feed.py

@@ -226,6 +226,7 @@ async def allocate_persistent_feed(
 
     loglevel: str,
     start_stream: bool = True,
+    init_timeout: float = 616,
 
     task_status: TaskStatus[FeedInit] = trio.TASK_STATUS_IGNORED,
 
@@ -267,6 +268,7 @@ async def allocate_persistent_feed(
     # TODO: probably make a struct msg type for this as well
     # since eventually we do want to have more efficient IPC..
     first_quote: dict[str, Any]
+    with trio.fail_after(init_timeout):
         (
             init_msgs,
             first_quote,
@@ -908,6 +910,7 @@ async def open_feed(
 
                 for fqme, flume_msg in flumes_msg_dict.items():
                     flume = Flume.from_msg(flume_msg)
+
                     # assert flume.mkt.fqme == fqme
                     feed.flumes[fqme] = flume