Accelerate devcontainer experience by building and hosting gadgetron_dev_cuda_oot

[Andrew-Dupuis]

The longest part of initializing the devcontainer for this project is configuration of the oot working environment. We should build and host the interstitial tag "gadgetron_dev_cuda_oot" (as well as a non-cuda version) so that starting the devcontainer doesnt require building the conda environment.

[Andrew-Dupuis]

For the sake of the HackMR event, an image with the tag "ghcr.io/gadgetron/gadgetron/gadgetron_ubuntu_dev_cuda_oot:latest" has been built and pushed to serve as a cachepoint for the devcontainer so folks don't need to rebuild the conda environment. We'll need to add a build runner to make this automatically update, likely on the Gadgetron main repo or similar - however, that isn't worth doing until we resolve #2 .