Change span names in HTTP instrumentation package to conform with guidelines

[humivo]

Changed the transport formatter so that the spans created by the HTTP instrumentation package conforms to the spec guidelines (Issue #726)

[codecov-commenter]

Codecov Report

Merging #620 (c13f657) into main (a51c8df) will decrease coverage by 0.0%.
The diff coverage is 88.8%.

@@           Coverage Diff           @@
##            main    #620     +/-   ##
=======================================
- Coverage   78.4%   78.4%   -0.1%     
=======================================
  Files         60      62      +2     
  Lines       2712    2737     +25     
=======================================
+ Hits        2128    2146     +18     
- Misses       452     456      +4     
- Partials     132     135      +3     

Impacted Files	Coverage Δ
detectors/gcp/gke.go	0.0% <ø> (ø)
propagators/aws/xray/propagator.go	65.1% <ø> (ø)
propagators/ot/ot_propagator.go	94.3% <ø> (-0.2%)	⬇️
propagators/b3/context.go	66.6% <66.6%> (ø)
propagators/jaeger/context.go	66.6% <66.6%> (ø)
...entation/github.com/go-kit/kit/otelkit/endpoint.go	83.7% <75.0%> (-1.7%)	⬇️
propagators/b3/b3_propagator.go	98.6% <96.9%> (+<0.1%)	⬆️
...tation/github.com/aws/aws-sdk-go-v2/otelaws/aws.go	95.1% <100.0%> (+0.1%)	⬆️
...ation/google.golang.org/grpc/otelgrpc/grpctrace.go	58.3% <100.0%> (ø)
...tion/net/http/httptrace/otelhttptrace/httptrace.go	100.0% <100.0%> (ø)
... and 4 more

[dashpole]

I think this is a dup of open-telemetry#757