Why: Cleanup for chttp2_transport ahead of promise conversion - lots of
logic has become interleaved throughout chttp2, so some effort to
isolate logic out is warranted ahead of that conversion.
What: Split configuration and policy tracking for each of ping rate
throttling and abuse detection into their own modules. Add tests for
them.
Incidentally: Split channel args into their own header so that we can
split the policy stuff into separate build targets.
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Co-authored-by: ctiller <ctiller@users.noreply.github.com>
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