added devcontainer support

[niposch]

I experimented with VS Code's devcontainers, and I was pleasantly surprised. Got this project up and running and even got the gui to show up on my Windows desktop despite the application running inside a docker container. Breakpoints also work.

Setup is pretty straight forward: have docker and VS Code + devcontainer extension installed.
Have the extension set up a dev container. It will set up the environment according to what is specified in the config files, which should make it a lot easier for people to start writing code without having to worry about setting everything up correctly, as the project can set itself up inside a docker container.

The setup works very well on Windows 11 (can't comment on older versions/other operating systems) but it would allow someone who isn't quite as familiar with how to get the project compiled/get all the dependencies installed up and running.

Feel free to reject if this isn't something the project is interested in.

[trollixx]

I haven't used devcontainer stuff in VS Code, but it seems to be not that different from building in WSL directly. I don't think IDE specific setup should be part of the main repo. A wiki page with instructions would be a better fit. Thanks.