Dev container suggestions

Some suggestions for the dev container setup (happy to prep a PR if agreed): ## `venv.sh` static tasks As `venv.sh` is ran every time a container is created, static (and potentially slow) tasks are better to be moved to the Dockerfile, these include: - setting up the venv - Installing pip, node, rust, ipykernel, ... ## Building C++ separately from python At the moment ```bash QDK_UARCH=native pip install -v .[all] ``` builds C++ and python bindings together. But it might be nicer already here to install C++ separately and link the python build to it, which should allow for faster development. (At the moment I'm basically doing this manually anyway and ignoring the current install step.)