Log epoch height view

[zhangchiqing]

This PR adds some height and view to the logs when epoch events happen.

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 33.33333% with 8 lines in your changes missing coverage. Please review.

Project coverage is 41.75%. Comparing base (d32b10e) to head (19417cd).

Files	Patch %	Lines
network/p2p/cache/protocol_state_provider.go	33.33%	8 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #6095      +/-   ##
==========================================
- Coverage   41.75%   41.75%   -0.01%     
==========================================
  Files        1971     1971              
  Lines      138619   138628       +9     
==========================================
+ Hits        57877    57878       +1     
- Misses      74733    74749      +16     
+ Partials     6009     6001       -8     

Flag	Coverage Δ
unittests	41.75% <33.33%> (-0.01%)	⬇️

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[AlexHentschel]

@zhangchiqing I am curious if this code is actually related to the networking layer?

It seems like a general-purpose logging of epoch-related changes. If that is the case, I would recommend a proper separation of concerns:

• you can implement a simple consumer for the protocol events, and subscribe it to the pub-sub events.Distributor:

  flow-go/cmd/node_builder.go

  Line 200 in 19417cd

  ProtocolEvents *events.Distributor

  I think this would be a good example:

  flow-go/cmd/collection/main.go

  Lines 619 to 620 in 19417cd

  	heightEvents := gadgets.NewHeights()
  	node.ProtocolEvents.AddConsumer(heightEvents)

[zhangchiqing]

@AlexHentschel I moved the logging to a events logger module