Alarm server -connect_secs and -stable_secs settings

[kasemir]

Follow-up to #2597

The config and status messages are a kafka stream.
To get the "current" configuration, we wait until there is a pause in config messages.
Similarly, the alarm server waits for a pause in state messages to assume it knows the initial alarm state.

This timeout was 4 seconds, and #2597 made it configurable.
The actual issue, however, was a slow connection which required about 10 seconds until receiving the first message.

This adds separate "-connect_secs and -stable_secs command line parameters.
-connect_secs, default 10, configures the wait for the initial message, while -stable_secs is then used to wait for a pause in messages.

These parameters apply to the -import, -export and also the alarm server startup.