陳昱霖(Yu-Lin Chen)

[YUNIKORN-2503] Use internal annotation prefix for placeholder pod

2

### What is this PR for? Based on the design doc in [YUNIKORN-1351](https://issues.apache.org/jira/browse/YUNIKORN-1351) . 1. Remove label 'placeholder' in placeholder pod 2. Reanme placeholder's annotation to 'yunikorn.apache.org/placeholder' to 'internal.yunikorn.apache.org/placeholder' (2024/03/30...

[YUNIKORN-2504] Support canonical labels for queue/applicationId in scheduler

1

### What is this PR for? Support canonical Queue/ApplicationId labels in Pod, allows it coexist with the existing metadata. - yunikorn.apache.org/app-id (New, **Canonical Label**) - yunikorn.apache.org/queue (New, **Canonical Label)** YuniKorn...