Fix Docker container after adding -latomic

[eric846]

In #1309 we added -latomic -lrt, but this caused #1312. The binaries in the Docker image can no longer start, failing to find libatomic.so.1.

apk add libatomic in the Docker container does not work because of unknown Alpine Linux issues.

Instead we now build separate static versions of the Nighthawk binaries, solely for the Nighthawk in Docker.

Statically linking may lead to problems: https://groups.google.com/g/envoy-users/c/XK9M-RhWrxg/m/bgvUqtG2BwAJ.

Confirmed that the static Nighthawk binaries solve the libatomic.so.1 error and apparently fully start:

ci/do_ci.sh docker
...
docker run envoyproxy/nighthawk-dev:latest nighthawk_client
Bad argument: A URI or --multi-target-* options must be specified.

It is worth a try publishing this version, since it can't get worse than the status quo where the Nighthawk Docker image doesn't work.

If the statically linked version fails, another possibility is to switch to Ubuntu as in https://github.com/envoyproxy/envoy/blob/main/ci/Dockerfile-envoy.

[zirain]

@eric846 can you add a check for the CI?

docker run envoyproxy/nighthawk-dev:latest nighthawk_client --help

[eric846]

@eric846 can you add a check for the CI?

docker run envoyproxy/nighthawk-dev:latest nighthawk_client --help

Will find a place to add this. #1317

[eric846]

Now that we have a known-good Ubuntu workaround in #1312, I can try to migrate the container to Ubuntu, which is simpler.

[eric846]

Closing in favor of #1315.