Plugins: Rename oauth package to auth (#75611)

* Plugins: Rename oauth package to auth

* Missed one comment

pkg/plugins/auth/models.go

@@ -0,0 +1,17 @@
+package auth
+
+import (
+	"context"
+
+	"github.com/grafana/grafana/pkg/plugins/plugindef"
+)
+
+type ExternalService struct {
+	ClientID     string `json:"clientId"`
+	ClientSecret string `json:"clientSecret"`
+	PrivateKey   string `json:"privateKey"`
+}
+
+type ExternalServiceRegistry interface {
+	RegisterExternalService(ctx context.Context, name string, svc *plugindef.ExternalServiceRegistration) (*ExternalService, error)
+}