Add bandwidth testing

[egieseke]

Summary

To support performance testing with bandwidth collection, updated Hello World recipe so that it works, and specify UTF-8 encoding when processing metrics files.

Test Plan

Tested using pipeline https://ci.algorand.network/job/cicd-perf-pprof/87/

[codecov-commenter]

Codecov Report

Merging #3487 (04ef390) into master (2346615) will increase coverage by 0.00%.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master    #3487   +/-   ##
=======================================
  Coverage   47.65%   47.65%           
=======================================
  Files         370      370           
  Lines       59804    59804           
=======================================
+ Hits        28498    28499    +1     
  Misses      28001    28001           
+ Partials     3305     3304    -1     

Impacted Files	Coverage Δ
catchup/service.go	69.90% <0.00%> (-0.75%)	⬇️
network/wsPeer.go	68.05% <0.00%> (-0.56%)	⬇️
ledger/acctupdates.go	65.01% <0.00%> (+0.19%)	⬆️
agreement/proposalManager.go	98.03% <0.00%> (+1.96%)	⬆️
agreement/cryptoVerifier.go	70.21% <0.00%> (+2.12%)	⬆️

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