Devcontainer for OpenCloud

[sdwilsh]

Is your feature request related to a problem? Please describe.

Not everyone has a Go toolchain ready to go to contribute code changes to this repository. A Devcontainer can trivially produce an environment that "just works" for contributors. This is especially useful for anybody running an immutable Linux like Bluefin.

Describe the solution you'd like

vscode supports Devcontainers very well, and I believe other editors have started to do the same. I have a working container that I made in order to make #1724 that I can upstream as a starting point that provides a working Go toolchain.

Describe alternatives you've considered

Better contributing documentation on how to setup the environment would be helpful if this isn't desired.

Additional context

Add any other context or screenshots about the feature request here.

[micbar]

Thank you for the proposal. A pull request is welcome!