Add verification and testing targets for CI

[ixdy]

This PR updates make test to use gotestsum (for better test reporting), including automatically generating junit when run in the Prow environment.

It also adds several verification checks, wrapped by the make verify rule:

• verify-boilerplate, imported from repo-infra (without using the bazel target)
• verify-lint, which uses golangci-lint (with possibly too many linters enabled; further tuning may be necessary)
• verify-modules, which ensures that the go modules files are up-to-date.

After this is in, we should be able to create one or more Prow jobs that run make build, make test, and make verify.

/assign @alvaroaleman

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: ixdy

The full list of commands accepted by this bot can be found here.

The pull request process is described here

Needs approval from an approver in each of these files:

• OWNERS [ixdy]

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment

[alvaroaleman]

I think the leading ! is wrong?

[ixdy]

the parens were weird (I basically copied this from a Makefile) so I've now removed them, but otherwise this should do the right thing - git exits 0 if no diff, nonzero if diff, so we want to invert that.

[alvaroaleman]

TILd

[ixdy]

this is maybe too clever, but it works for now...

[alvaroaleman]

/lgtm
We should activate that the github review can be used to approve