Add private OCI registry authentication

[bradkwadsworth-mw]

1. Does this PR affect any open issues?(Y/N) and add issue references (e.g. "fix #123", "re #123".):

• N
• Y
  fix [Enhancement] Private OCI Source Support for KRM KCL Spec #32

2. What is the scope of this PR (e.g. component or file name):

pkg/config

3. Provide a description of the PR(e.g. more details, effects, motivations or doc link):

• Affects user behaviors
• Contains syntax changes
• Contains variable changes
• Contains experimental features
• Performance regression: Consumes more CPU
• Performance regression: Consumes more Memory
• Other

Provider login credentials for private OCI registries.

4. Are there any breaking changes?(Y/N) and describe the breaking changes(e.g. more details, motivations or doc link):

• N
• Y

5. Are there test cases for these changes?(Y/N) select and add more details, references or doc links:

• Unit test
• Integration test
• Benchmark (add benchmark stats below)
• Manual test (add detailed scripts or steps below)
• Other

apiVersion: krm.kcl.dev/v1alpha1
kind: KCLRun
metadata:
  name: webapp
spec:
  params:
    metadata:
      name: "demo"
    containers:
      nginx:
        image: nginx
        ports:
          - containerPort: 8080
    service:
      ports:
        - port: 8080
  source: oci://<private module>
  credentials:
    url: https://<private registry login url>
   username: <username>
  password: <password>

[Peefy]

LGTM

[Peefy]

Thank you for the contribution. ❤