Validate monitor config values and send max changes configuration on startup

[Charles-Gagnon]

1. Validate batchsize/polling interval configuration like we do for Max Changes per Worker. Doing same check (> 0) for now - we could consider having "special" values supported in the future like a polling interval of 0 meaning no delay between batches and -1 batch size meaning no limit, but until we can actually spend some time testing that it doesn't seem necessary and could easily lead to issues
2. Send max changes per worker configuration in startup event like we do for the other configurations so we can see whether people are changing these values and to what