Fix (and merge) Dockerfiles, adds a CI job for building and uploading docker images

[guillaumedsde]

📝 Description

Hello 👋

This PR corrects an issue with the repository's Dockerfiles: the final images don't include the glibc dependency due to them using the slim variant of the debian image as the base.
The consequence of this is that the lidis/r binaries crash on startup when running the docker images built from this repository's Dockerfiles, moreover no docker image is published on the docker hub.

Note that it might be desirable to squash the commits when merging, the commit history is ok, but not ideal

✔️ Changelog

The PR addresses this by:

• rewriting the Dockerfiles into a single multi-stage Dockerfile (one stage for the send binary, another for the receive binary)
• using one of Google's "distroless" docker image as the base for the final images.
  • the CC image used here, includes
    • ca-certificates
    • A /etc/passwd entry for a root user
    • A /tmp directory
    • tzdata
    • glibc
    • libgcc1 and its dependencies.
• switching to a non-root user for the final docker images
• adding a CI job for building, tagging and publishing the final two docker images (send/receive) to the dockerhub
  • note that the username/password variable names for logging into the dockerhub are the same ones as used in eurydice and they should be added in the lidi's github repository's configuration

🥼 Tests

Note that I have tested the Github action logic for build, tagging and pushing the docker images but in my own fork (since I don't have access to this repo's CI). During my tests (which consisted of building and uploading the image's to my repo's github registry) everything worked as exepcted.