Add dev-container to streamline development environment

[oliverlorenz]

I use more and more dev-containers to streamline the development environment with essential tools and features. Dev Containers provide a consistent, isolated, and version-controlled development environment that works across platforms and eliminates “works on my machine” issues. It's very handy, and I would love to bring that upstream to also use it here.

• ansible, ansible-lint, just, pwgen and pre-commit are already built in and ready to use
• Unfortunately, agru is missing at the moment.
• With the dev-container start up, the pre-commit hook is installed and the roles are got by just roles
• .ssh directory is mounted readonly so ssh connections should work as in local environment

Guide to test

• open vscode
• install Dev Containers Extension
• File -> Open Folder. Open mash-playbook
• A popup in the right bottom corner should appear. Click "Reopen in Container"
• vscode will restart and build the container
• Now the fully encapsulated dev environment is running

Let me know what you are thinking 🙂