record_play_mixer: reduce volume of diagnostic messages by default

[nfeske]

In Sculpt, the latency warnings by the record-play mixer are too many (rate of 1 second). Those warnings were intended for diagnosis. But Sculpt users will hardly participate in the debugging of latency issues but have to ensure all his warning noise.

To address this issue, a warning_rate_ms attribute could be added to the record_play_mixer config. By using 10000 ms default, regular users won't be bothered when seeing a message every now and then. But for latency diagnosis, we can set the attribute even to a low value like 200 ms.

Related to #5174

[chelmuth]

I would even be more user-oriented and implement warning_rate_ms as mere debugging feature with a default of 0 (no warnings).

[nfeske]

@cnuke what do you think?

[nfeske]

@chelmuth this would be fine for me as well.

[cnuke]

@nfeske I think that is a good idea (introducing the feature and setting it to 0 be default).