Add startup-query-interval and startup-query-count support

[troglobit]

In many setups the initial query sent by mcd on link up is lost. This involves both various physical switches and the Linux bridge. The latter might drop initial frame(s), due to the NOOP qdisc being set as the default.

A common fix for both is to add support for RFC3376 style startup-query-interval and startup-query-count. I.e., on first link up, send more queries to ensure all devices on the LAN (and locally) learn about our querier.

For details, see https://datatracker.ietf.org/doc/html/rfc3376#section-8.6