stats: track additional QUIC counter events

[afrind]

Wire onPacketProcessed, onPTO, onPacketSpuriousLoss, onPersistentCongestion, onConnectionWritableBytesLimited, onConnectionRateLimited, onPacerTimerLagged, and onUDPSocketWriteError into the stats data structures instead of no-opping. Split quicPacketRetransmissions into timerLosses/spuriousLosses in pico path.

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This change is 

[gmarzot]

@gmarzot reviewed 4 files and all commit messages.
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[afrind]

@afrind made 1 comment.
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src/stats/QuicStatsCollector.cpp line 116 at r1 (raw file):

      ++data_->quicSocketWriteNobufs_;
    }
  }

Let's add quicSocketWriteOther_ or quicSocketWriteTotal_ to capture other errors

[afrind]

@afrind resolved 1 discussion.
Reviewable status: 2 of 4 files reviewed, all discussions resolved (waiting on gmarzot, michalhosna, mondain, Oxyd, peterchave, suhasHere, and TimEvens).