Add Makefile targets to run CI tests locally

[patgmiller]

New MR to replace #902 b/c rewriting history didn't fix test message failures.

See issue #897 and discussion #892 for background. Basically add ability to run make test and make test-coverage locally using docker containers.

Added make targets:

• test-go: This will run the test-coverage for related GO_VERSION environment variable.
• test-git: This will build git distribution for GIT_VERSION environment variable and then run make test against it.
• test-env: ran by test-go and test-git to build required environment setup.

@pjbgf I will apply the remaining changes here, thanks.

[patgmiller]

@pjbgf see link to previous question about using new make targets in automated testing.