Also disable master-2-16-32-{att,dt,tt} jobs that hang on inactive blade hardware

Makefile
makefiles/target/
-----------------
  o Refactor Makefile, move target logic into makefiles/targets/{target-name}.mk
  o Add context specific help -> makefile target: help-{target-name}

Change-Id: Ib00975e56488c7c23ebc01963002be59a7e3c97c
diff --git a/makefiles/targets/clean.mk b/makefiles/targets/clean.mk
new file mode 100644
index 0000000..f504dec
--- /dev/null
+++ b/makefiles/targets/clean.mk
@@ -0,0 +1,40 @@
+# -*- makefile -*-
+# -----------------------------------------------------------------------
+# Copyright 2022-2023 Open Networking Foundation (ONF) and the ONF Contributors
+#
+# 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.
+#
+# SPDX-FileCopyrightText: 2022 Open Networking Foundation (ONF) and the ONF Contributors
+# SPDX-License-Identifier: Apache-2.0
+# -----------------------------------------------------------------------
+
+$(if $(DEBUG),$(warning ENTER))
+
+## -----------------------------------------------------------------------
+## Intent: Remove makefile generated content
+## -----------------------------------------------------------------------
+.PHONY: clean
+clean ::
+	$(RM) -r $(JOBCONFIG_DIR)
+
+## -----------------------------------------------------------------------
+## -----------------------------------------------------------------------
+help-verbose += help-clean
+help-clean ::
+	@echo
+	@echo '[MAKE: clean]'
+	@echo '  clean               Remove makefile generated content'
+
+$(if $(DEBUG),$(warning LEAVE))
+
+# [EOF]