Since this is a recurrent topic and we are mainly operating by tribal
knowledge, I think that is good to have it written so we can use it as
reference for future discussions.
Change-Id: I300b06d82a1064bfc3b5bc904f02f8b786cd5480
Previously, information on running unit and integration tests lived in
the testing.md doc, while information on running e2e tests lived in its
own doc. The testing.md doc is getting large, and particularly since its
a doc that many new members of the project look at, I think there's a
lot of benefit to keeping it concise.
To accomplish this, move information around running integration tests
into integration-tests.md, and then link to said document from
testing.md. This allows a new member of the project to get up and
running with unit tests, and then explore integration/e2e testing as
they have the need.
Improve the testing documentation in the following ways:
1. Ensure all of the given commands actually work. Some of them
specified tests that no longer existed or packages that no longer had
tests.
2. Clarify the ability to run tests for a package and all its
subpackages with `/...`.
3. Clarify how the developer can also utilize `go test` if they desire.
It looks like some links were not updated when `devel/sig-testing` was
created and populated with documentation.
Additionally, move `gubernator-images` to `devel/sig-testing`, as only
the `gubernator.md` file uses these images, and it now lives in
`devel/sig-testing`.