add basic configuration with demo_package

.devcontainer/Dockerfile

.devcontainer/devcontainer.json

.env

.gitignore

.vscode/settings.json

README.md

camera-task/.gitignore

camera-task/.prepare-env.sh

camera-task/src/avai_messages/CMakeLists.txt

camera-task/src/avai_messages/package.xml

camera-task/src/demo_package/demo_package/__init__.py

camera-task/src/demo_package/demo_package/pub.py

camera-task/src/demo_package/demo_package/sub.py

camera-task/src/demo_package/package.xml

camera-task/src/demo_package/resource/demo_package

camera-task/src/demo_package/setup.cfg

camera-task/src/demo_package/setup.py

camera-task/src/demo_package/test/test_copyright.py

camera-task/src/demo_package/test/test_flake8.py

camera-task/src/demo_package/test/test_pep257.py