otlptracehttp v2

[pellared]

The scope of this issue is to create a new otlptracehttp v2 module which would have API similar to otlpmetrichttp and it will not depend on google.golang.org/grpc.

Unfortunately, it is not possible (without making a breaking change) to remove the dependency on google.golang.org/grpc in otlptracehttp because of https://pkg.go.dev/go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracehttp#NewClient as https://pkg.go.dev/go.opentelemetry.io/otel/exporters/otlp/otlptrace#Client exposes the proto package which depends on google.golang.org/grpc.

The fix would require creating v2 modules. For oteltracehttp and oteltracegrpc. After these are created we still need to support the v1 modules for at least a year. I think for ease of review we should create the new v2 modules of oteltracehttp and oteltracegrpc "from scratch" (similar to otelloghttp). I will create issues once I have a little more time.

More: #5221

Originally posted by @pellared in #2579 (comment)