kp build logs should support one-off builds

[ekcasey]

The kpack API supports one-off imperative builds with the Build resource, without requiring the creation of an Image resource. This is especially useful for debugging, when it is sometimes convenient to recreate an issue with a pre-built builder image created by pack or another instance of kpack.

To improve this debugging experience, I would like to be able to see the build logs with kp build logs even when I have created the build imperatively.

I am not sure what the least awkward interface is. Maybe one of the following?

kp build logs --build-name my-build
kp build logs my-build # looks for builds if it can't find an image
kp build logs my-build --kind build # kinda weird, probably not the best