Allow disabling HTTP/2 priority frames limit

[jvgutierrez]

As discussed yesterday on Slack, there are some scenarios, specially when proxy.config.http2.stream_priority_enabled is set to 0 where disabling HTTP/2 priority frames limit is interesting. This PR allows to disable it by setting proxy.config.http2.max_priority_frames_per_minute to 0

[sudheerv]

For consistency and completeness, I think we should've similar disable mechanism for rate limiting the Settings, Ping, Error Rate as well.

[bryancall]

[approve ci autest]

[zwoop]

@jvgutierrez Would you mind making similar changes for the other rate limiting settings ? If not, I'm ok landing this, and make a separate PR.

[zwoop]

Also, it feels that if proxy.config.http2.stream_priority_enabled == 0, we ought to ignore the frames rather than rate limiting them ?

[jvgutierrez]

Also, it feels that if proxy.config.http2.stream_priority_enabled == 0, we ought to ignore the frames rather than rate limiting them ?

PR updated, now the limit is only enforced if proxy.config.http2.stream_priority_enabled is set to 1, otherwise the frames are just ignored.

[shinrich]

Looks good to me. Unfortunately, the PR needs to be rebased due to other merges causing conflicts.

[jvgutierrez]

Looks good to me. Unfortunately, the PR needs to be rebased due to other merges causing conflicts.

done!

[zwoop]

Cherry-picked to v9.0.x branch.