NOTICE and COPYRIGHT_HEADER.txt added (UTBot CPP) (#558)

* NOTICE and COPYRIGHT_HEADER added

Author: olganaumenko

COPYRIGHT_HEADER.txt

@@ -0,0 +1,15 @@
+/*
+ * Copyright 2022 UnitTestBot contributors (utbot.org)
+ *
+ * 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.
+ */

NOTICE

@@ -0,0 +1,2 @@
+UnitTestBot
+Copyright 2022 UnitTestBot contributors (utbot.org)