Add Dockerfile and corresponding workflow

[namannimmo10]

This is an attempt to build and push a docker image to the GitHub container registry using nvidia/cuda:11.6.2-devel-ubi8 as a base image. This newly built image can then be used for our GA workflows.

[namannimmo10]

OK, the workflow succeeded. From the logs:

pushing ghcr.io/diamondlightsource/httomolibgpu:dockerfile with docker

[yousefmoazzam]

Cool! 🎉 Can indeed see the built container image in https://github.com/diamondlightsource/httomolibgpu/pkgs/container/httomolibgpu

[dkazanc]

thanks @namannimmo10 , so currently nothing is running in the container but it has got the conda environment for httomolibgpu?

[namannimmo10]

No this doesn't contain the dependencies for httomolibgpu. Hopefully, this will fix the issue we're having with #140 where git is unavailable. But similar approach could be followed to create a docker image for the library itself.

[namannimmo10]

OK, this PR serves the purpose, I will merge it. We can certainly create an image for the library and push it with a different tag. This workflow won't run on the main branch.