Jaeger http thrift

[axw]

Add an HTTP handler, muxer, and server, in beater/jaeger for accepting Thrift-encoded trace data over HTTP. Refactor beater/jaeger.GRPCServer into Server, which now encapsulates both gRPC and HTTP servers.

Move beater/api/jaeger code into beater/jaeger, which is the only user of GRPCCollector. If the beater/jaeger code grows significantly, we might consider having subpackages like beater/jaeger/grpc, beater/jaeger/http, etc.

Config has been updated to accommodate both gRPC and HTTP. Config now looks like this:

jaeger:
  grpc:
    # Set to true to enable the Jaeger gRPC collector service.
    enabled: false
    # Defines the gRPC host and port the server is listening on.
    # Defaults to the standard Jaeger gRPC collector port 14250.
    host: "localhost:14250"
  http:
    # Set to true to enable the Jaeger HTTP collector endpoint.
    enabled: false
    # Defines the HTTP host and port the server is listening on.
    # Defaults to the standard Jaeger HTTP collector port 14268.
    host: "localhost:14268"

Tests have been simplified to use mock TraceConsumers, rather than relying on the concrete processor/otel.Consumer. They're integrating less now; we can test the whole process in system tests.

I regenerated the TLS certificates under testdata, as the CA certificate did not appear to be related to the certificate. TLS wasn't being enabled correctly before - that's been fixed now, with tests added that prove it's enabled.

Closes #3008

[codecov-io]

Codecov Report

Merging #3081 into jaeger will increase coverage by 0.18%.
The diff coverage is 84.24%.

@@            Coverage Diff             @@
##           jaeger    #3081      +/-   ##
==========================================
+ Coverage   79.27%   79.45%   +0.18%     
==========================================
  Files         101      103       +2     
  Lines        5279     5365      +86     
==========================================
+ Hits         4185     4263      +78     
- Misses       1094     1102       +8

Impacted Files	Coverage Δ
beater/jaeger/grpc.go	100% <100%> (+17.24%)	⬆️
beater/api/mux.go	81.96% <100%> (ø)	⬆️
beater/request/context_pool.go	100% <100%> (ø)
beater/server.go	73.91% <33.33%> (+3.07%)	⬆️
beater/jaeger/server.go	80% <80%> (ø)
beater/jaeger/common.go	80% <80%> (ø)
beater/config/jaeger.go	89.47% <84.61%> (+3.75%)	⬆️
beater/jaeger/http.go	91.07% <91.07%> (ø)
... and 1 more

[simitt]

Code looks great!

Only found some typo, for which it is concerning that data are properly decoded with the typo.

[axw]

@simitt I moved the approvals test into beater/jaeger as well, inside server_test.go, in ad31536. The test now also runs through the HTTP/Thrift endpoint.