Support Groups as Subject Kind for Tenant Namespace RoleBindings created by Capsule (#71)

Modified CRD to support Owner struct.

Added Tenant name validation webhook.

Rewrote owner_reference hook logic.

Updated and added new e2e tests.

Co-authored-by: Maksim Fedotov <m_fedotov@wargaming.net>

pkg/utils/owner.go

@@ -0,0 +1,23 @@
+/*
+Copyright 2020 Clastix Labs.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package utils
+
+import "github.com/clastix/capsule/api/v1alpha1"
+
+func GetOwnerWithKind(tenant *v1alpha1.Tenant) string {
+	return tenant.Spec.Owner.Kind.String() + ":" + tenant.Spec.Owner.Name
+}