spike building fips binary

What does this MR do?

This is a spike for conditional compilation of FIPS compliant GitLab Runner binary.

To build with boringssl run:

docker build -f dockerfiles/runner/fips/Dockerfile --build-arg DOCKER_MACHINE_VERSION=0.16.2 --build-arg DUMB_INIT_VERSION=1.2.2 --build-arg GIT_LFS_VERSION=2.11.0 -t runner-fips .

Or with rhel tooling:

docker build -f dockerfiles/runner/fips/rhel.Dockerfile --build-arg DOCKER_MACHINE_VERSION=0.16.2 --build-arg DUMB_INIT_VERSION=1.2.2 --build-arg GIT_LFS_VERSION=2.11.0 -t rhel-runner-fips .

Then start a container with the respective image:

docker run --rm -it rhel-runner-fips

Register the runner by ssh-ing into the container:

docker exec -it <CONTAINERID> bash

gitlab-runner register

With RHEL you should have no problems, with boringssl you will see an error:

ERROR: Registering runner... failed                 runner=9LTwPrry status=couldn't execute POST against https://gitlab.com/api/v4/runners: Post "https://gitlab.com/api/v4/runners": x509: certificate specifies an incompatible key usage

Why was this MR needed?

Spike for gitlab#296017 (closed)

What's the best way to test this MR?

What are the relevant issue numbers?