feat(MeshHTTPRoute): basic MeshGateway support

[michaelbeaumont]

Leaves out the filters and more complex matches for another PR.

This expects routes like:

targetRef:
  kind: MeshGateway
  name: edge
to:
- targetRef:
    kind: Mesh
  rules:
  ...

Checklist prior to review

• Link to relevant issue as well as docs and UI issues -- Support MeshHTTPRoute/MeshTCPRoutes with MeshGateways #8142
• This will not break child repos: it doesn't hardcode values (.e.g "kumahq" as a image registry) and it will work on Windows, system specific functions like syscall.Mkfifo have equivalent implementation on the other OS --
• Tests (Unit test, E2E tests, manual test on universal and k8s) --
  • Don't forget ci/ labels to run additional/fewer tests
• Do you need to update UPGRADE.md? --
• Does it need to be backported according to the backporting policy? (this GH action will add "backport" label based on these file globs, if you want to prevent it from adding the "backport" label use no-backport-autolabel label) --

[lobkovilya]

MeshHTTPRoute doesn't support kind: MeshGateway in the top-level targetRef, right? I'm a bit lost, why some policies like MeshTimeout/MeshRetry have kind: MeshGateway but MeshHTTPRoute uses just kind: MeshService to target MeshGateway?

[lobkovilya]

Is it going to work if MeshTimeout targets MeshHTTPRoute and MeshHTTPRoute targets MeshGateway?

[michaelbeaumont]

MeshHTTPRoute doesn't support kind: MeshGateway in the top-level targetRef, right?

Not yet, I need to add that validation to this PR, but ran into #8438. The intention is to support MeshGateway as well.

I'm a bit lost, why some policies like MeshTimeout/MeshRetry have kind: MeshGateway but MeshHTTPRoute uses just kind: MeshService to target MeshGateway?

This is just #6956 not being done

[lobkovilya]

LGTM