Add resource relationship to app model

[JamesNK]

Description

This PR adds:

• Relationship annotation and WithRelationship extension method to app model
• WithRelationship calls are in various methods that add or reference resources.
• Relationship field to resource service proto contract
• Relationship field to ResourceViewModel.
• UI to resource details to display References and Back references
• Color to resource name on resources page and resource names in detail's references UI

Checklist

• Is this feature complete?
  • Yes. Ready to ship.
  • No. Follow-up changes expected.
• Are you including unit tests for the changes and scenario tests if relevant?
  • Yes
  • No
• Did you add public API?
  • Yes
    • If yes, did you have an API Review for it?
      • Yes
      • No
    • Did you add <remarks /> and <code /> elements on your triple slash comments?
      • Yes
      • No
  • No
• Does the change make any security assumptions or guarantees?
  • Yes
    • If yes, have you done a threat model and had a security review?
      • Yes
      • No
  • No
• Does the change require an update in our Aspire docs?
  • Yes
    • Link to aspire-docs issue:
  • No

Microsoft Reviewers: Open in CodeFlow

[mitchdenny]

From an app model perspective I am happy with where this is at except for the XML doc comments ;)