Define http.Server.ErrorLog to forward logs to Zap

[yurishkuro]

Related to #3156

[codecov]

Codecov Report

Merging #3157 (c4c7d8d) into master (605c1f1) will decrease coverage by 0.00%.
The diff coverage is 84.21%.

@@            Coverage Diff             @@
##           master    #3157      +/-   ##
==========================================
- Coverage   95.95%   95.94%   -0.01%     
==========================================
  Files         239      239              
  Lines       14624    14647      +23     
==========================================
+ Hits        14032    14053      +21     
- Misses        515      518       +3     
+ Partials       77       76       -1     

Impacted Files	Coverage Δ
cmd/collector/app/server/zipkin.go	70.73% <0.00%> (-4.95%)	⬇️
cmd/query/app/server.go	95.58% <91.66%> (+1.61%)	⬆️
cmd/agent/app/builder.go	96.07% <100.00%> (ø)
cmd/agent/app/httpserver/srv.go	100.00% <100.00%> (ø)
cmd/collector/app/server/http.go	100.00% <100.00%> (ø)
cmd/flags/admin.go	82.81% <100.00%> (+1.45%)	⬆️
...lugin/sampling/strategystore/adaptive/processor.go	99.35% <0.00%> (-0.65%)	⬇️

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[yurishkuro]

codecov is lying about coverage change