Part of #6494

In Jaeger the domain model is generated in model/model.pb.go from model.proto but then enriched with all kinds of business functions / helpers. To ease the transition of the existing code to the new jaeger-idl/model/v1 package we should copy all those helpers (a minimal required set was done in jaegertracing/jaeger-idl#118).

After copying and running go mod tidy there should be no new dependencies in go.mod. We should avoid copying some functions that have external dependencies, like translations between model IDs and OTEL IDs.

As there are many different files in model/, it's best to do this incrementally, not as a single PR.

model/dependencies.go
model/hash.go
model/keyvalue.go
model/process.go
model/sort.go
model/span.go
model/spanref.go
model/time.go
model/trace.go