liveupdate: use ImageMap for Tilt-built image matching

[milas]

There's three supported Live Update K8s selector configurations:
(1) Tilt-built image (e.g. from docker_build or custom_build)
(2) External image (e.g. file_sync_only extension + nginx image)
(3) Container name (e.g. some k8s_custom_deploy configurations)

For (1) and (2), we match the container image against the image
selector in the v1alpha1.LiveUpdateKubernetesSelector. As a result,
this meant that for (1), the selector reference was the fully-qualified
"from-cluster" reference, i.e. using local registry.

For example, if the image is referred to in the Tiltfile as follows:

docker_build('gcr.io/foo/bar', ...)

Then the Tilt-built image might be something like
localhost:51245/gcr_io_foo_bar:tilt-123.

For (2), the image reference will be used as-is since it's not built
by Tilt.

While not relevant here, for completeness, for (3), the container name
is a direct comparison.

The v1alpha1.LiveUpdateKubernetesSelector is populated via a call
to ImageTarget::InferLiveUpdateProperties(). As a result, this needs
the registry information so that it could determine the proper image
name to use for the selector for (1).

This is problematic because the local registry initialization is no
longer guaranteed at startup - it's part of Cluster reconciliation
once the client connection is successfully established.

By adding a new option to the selector to pass a reference to an
ImageMap, we can grab the fully-qualified reference via
.Status.ImageFromCluster.

[milas]

This PR is super chonky as-is because there's codegen/reconciler stub/apiserver-to-state dispatch that was needed for the final solution to come together (which I wasn't 100% sure was going to work before doing it 😅)

I wanted to get a sanity check on the approach, and then I'll split it up into smaller PRs for review

[nicks]

LGTM!