api: minor improvement in logs using json.Decoder and less goroutines
api: minor improvement in logs using json.Decoder and less goroutines

benchmark             old ns/op     new ns/op     delta
BenchmarkScanLogs     31015         29015         -6.45%

benchmark             old allocs     new allocs     delta
BenchmarkScanLogs     25             22             -12.00%

benchmark             old bytes     new bytes     delta
BenchmarkScanLogs     1637          1333          -18.57%

guilhermebr/tsuru,ggarnier/tsuru,Endika/tsuru,ggarnier/tsuru,tsuru/tsuru,gwmoura/tsuru,cezarsa/tsuru,ArxdSilva/tsuru,tsuru/tsuru,tsuru/tsuru,cezarsa/tsuru,cezarsa/tsuru,guilhermebr/tsuru,ArxdSilva/tsuru,Endika/tsuru,gwmoura/tsuru,guilhermebr/tsuru,ggarnier/tsuru,ggarnier/tsuru,tsuru/tsuru,guilhermebr/tsuru,cezarsa/tsuru,ArxdSilva/tsuru,ArxdSilva/tsuru,gwmoura/tsuru,Endika/tsuru