TransactionScheduler: Scheduler Count and Timing metrics

[apfitzge]

Problem

• Currently no metrics for number of packets being received and scheduled by the scheduler
• Currently no metrics for amount of time spent in each code section in the scheduler

Summary of Changes

• Add metrics for number of packets received, dropped in different ways, scheduled etc
• Add metrics for amount of time spent in major code sections: decision-making, scheduling, receiving, buffering
• All metrics reports on a 1s interval

Fixes #

[codecov]

Codecov Report

Merging #33893 (c3ddff6) into master (ba112a0) will increase coverage by 0.0%.
Report is 144 commits behind head on master.
The diff coverage is 95.9%.

Additional details and impacted files

@@           Coverage Diff            @@
##           master   #33893    +/-   ##
========================================
  Coverage    81.8%    81.9%            
========================================
  Files         810      810            
  Lines      218148   218255   +107     
========================================
+ Hits       178650   178812   +162     
+ Misses      39498    39443    -55     

[tao-stones]

lgtm - a good starting with these new counters, and planned collected fee counter in separate PR. Can add/adjust as needed when testing