V2 Migration + additional refactoring.

[sivabalan19]

Description of your changes

Migration to V2 with additional refactoring.

API & Resource Updates

• XRD upgraded to apiextensions.crossplane.io/v2 with namespaced scope
• Resource renamed: XArgo → Argo (cleaner naming without X prefix)
• Parameter change: deletionPolicy → managementPolicies (more granular lifecycle control)
• Provider upgrades: helm and kubernetes providers upgraded from v0 to v1

KCL Function Refactoring

• Directory renamed: functions/xargo/ → functions/compose-argo/
• Updated imports: Now using v2 provider models (helmm, kubernetesm)
• ProviderConfig references now explicitly include kind field

Test & Example Updates

• Test directories renamed: test-xargo/ → test-argo/, e2etest-xargo/ → e2etest-argo/
• All tests updated for v2 APIs and passing
• Examples updated with new resource kind and parameters

Provider bump-up

• Dependent providers like Helm and Kubernetes to recent version to allow namespaced scope resources.

Breaking Changes

1. Resources are now namespaced instead of cluster-scoped
2. XArgo kind renamed to Argo
3. deletionPolicy parameter replaced by managementPolicies

• Read and followed Upbound's contribution process.
• Run make reviewable to ensure this PR is ready for review.
• Added backport release-x.y labels to auto-backport this PR, as appropriate.

How has this code been tested

configuration-gitops-argocd on  v2-migration [✘!?] 
⚡up test run tests/*
  ✓   Parsing tests                                                                                                                                                                       
  ✓   Collecting resources
  ✓   Generating language schemas
  ✓   Checking dependencies
  ✓   Building functions
  ✓   Building configuration package
  ✓   Pushing embedded functions to local daemon
  ✓   Assert Test 1 - Argo Composition
SUCCESS: 
SUCCESS: Tests Summary:
SUCCESS: ------------------
SUCCESS: Total Tests Executed: 1
SUCCESS: Passed tests:         1
SUCCESS: Failed tests:         0

[matthewgreenwaldagility]

@sivabalan19 Do you need any assistance with this PR?