Publish Docker images in parallel

[tijmenstor]

Currently, the GitHub workflow that publishes Docker images releases all Mongo versions sequentially. This is quite slow and could be improved by running them all in parallel. This can be done by using a matrix, however this can be a bit hard to configure.

• All parallel jobs need to have the gradle output. This needs to be uploaded from the main job as an artifact and downloaded in the parallel job(s).
• Correct Mongo Dockerfile should be used based on the version that needs to be released (4.4 needs Dockerfile v4, 5.0 needs Dockerfile v5)

Relevant piece of code can be found here
Link to GitHub matrix in workflows here