feat: implement multi-provider binding support for CRDs (#173)

[alokkumardalei-wq]

Description:

This pull request addresses Issue #173 by adding support for multi-provider bindings in kube-bind. It enables a single consumer cluster to bind and manage Custom Resources from multiple provider clusters without conflict.

Changes made:

API Extensions:

• Introduced ProviderID string in BindingResourceResponse (sdk/apis/kubebind/v1alpha2/bindingresponse_types.go).
• Introduced ProviderID (string) and IsDefault (bool) in APIServiceBindingSpec (sdk/apis/kubebind/v1alpha2/apiservicebinding_types.go).
• Updated CRD definitions via code generation.

Backend:

• Updated HandleResources in manager.go to retrieve the provider cluster's kube-system namespace UID and set it as ProviderID.
• Included ProviderID in the BindingResourceResponse payload handled by the HTTP server (handler.go).
• Populated ProviderID in the BindingResourceResponse secret generated by the UI binding flow in bindableresourcesrequest_controller.go.

CLI Binding Flow:

• Modified bind-apiservice plugin's createAPIServiceBindings function to map ProviderID and IsDefault into APIServiceBindingSpec.

Konnector Core Engine:

• Updated servicebindingbundle_reconcile.go to inject the target kube-system UID into the generated APIServiceBinding spec upon reconciling provider connections.
• Extended spec and status controllers (spec_controller.go and status_controller.go) in pkg/konnector/controllers/cluster/serviceexport/ to filter inbound syncing events. Controllers now only route resources that contain the provider.kube-bind.io/provider-id annotation matching their assigned ProviderID, or any resource if they hold the IsDefault flag.

Testing and Validation

• Validation: Verified via local build (make build) that all integration logic compiles cleanly across both CLI and Backend components.
• Testing: Ran make test locally to ensure no pre-existing component behaviors were negatively impacted. All changes cleanly integrate with existing dynamic resource syncing logic.

Fixes #173