Contributing the STM32 port (apache#7742)

* Contribute apps/stm32 application.

* Removed a useless file.

* STM32: Use Model Library Format in demo. Added test.

* STM32: Added quantized mnist test.

* STM32: Fixed apps/stm32/Makefile.

* STM32: Added quantized models test.

* STM32: Added tests to tests/scripts/task_python_microtvm.sh

* STM32: Listed specific files with lint.

* STM32: removed external copyright notices.

* STM32: Added missing ASF copyright notice.

* STM32: style fixes.

* STM32: more style fixes.

* STM32: fixed liny for C files.

* STM32: Does extern C help with cpplint.

* STM32: Fixed wrong LINT_C_FILE spelling.

* STM32: Still some lint fixes.

* STM32: more style.

* STM32: More fixes lint+formatting.

* STM32: cleanup.

* STM32: style cleanup.

* STM32: Moved ai_runner to the apps/stm32.

* Alignment with PR 7742

* lint cleanup.

* STM32: Use crt_backend_api.c with standalone build.

* STM32: Fixed the CI test.

* STM32: style fixes.

* STM32: Removed unused files.

* STM32: Moved to crt_backend_api

* STM32: style fix.

* STM32: style fix.

* Revert "STM32: Removed unused files."

This reverts commit d72f8e5.

Undo changes to c_backend_api/c_runtime_api.

* Revert "STM32: Moved to crt_backend_api"

This reverts commit 6c0e666.

Undo changes to the c_backend-api/c_runtime_api.

* stm32: aligned to micro TVM structure.

* stm32: improved the python style.

* stm32: cpplint fixes.

* stm32: Fixed the test

* stm32: style fixes.

* stm32: style fixes.

* stm32: style fixes.

* stm32: style fixes.

python/tvm/micro/contrib/stm32/__init__.py

@@ -0,0 +1,20 @@
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you 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.
+
+"""Module container of STM32 code generator."""
+
+from .emitter import CodeEmitter, get_input_tensor_name, get_output_tensor_name