Usage Stats: Add metrics to count enabled kms providers per kind (#43640)

* Usage Insights: Add metrics to count enabled kms providers per kind

* Add backwards compatibility

pkg/services/kmsproviders/kmsproviders.go

@@ -3,9 +3,17 @@ package kmsproviders
 import "github.com/grafana/grafana/pkg/services/secrets"
 
 const (
-	Default = "secretKey"
+	// Legacy is used for historical reasons (keeping backwards).
+	// In older versions, the default value was a non-valid identifier,
+	// so it was updated to a valid one. See Default.
+	Legacy = "secretKey"
+
+	// Default is the identifier of the default kms provider
+	// which fallbacks to Grafana's secret key. See the
+	// defaultprovider package for further information.
+	Default = "secretKey.v1"
 )
 
 type Service interface {
-	Provide() (map[string]secrets.Provider, error)
+	Provide() (map[secrets.ProviderID]secrets.Provider, error)
 }

pkg/services/kmsproviders/osskmsproviders/osskmsproviders.go

@@ -20,12 +20,12 @@ func ProvideService(enc encryption.Internal, settings setting.Provider) Service
 	}
 }
 
-func (s Service) Provide() (map[string]secrets.Provider, error) {
+func (s Service) Provide() (map[secrets.ProviderID]secrets.Provider, error) {
 	if !s.settings.IsFeatureToggleEnabled(secrets.EnvelopeEncryptionFeatureToggle) {
 		return nil, nil
 	}
 
-	return map[string]secrets.Provider{
+	return map[secrets.ProviderID]secrets.Provider{
 		kmsproviders.Default: grafana.New(s.settings, s.enc),
 	}, nil
 }