Create stable release tags for R2DT Docker image

[AntonPetrov]

Currently there is a process for manually assigning a stable tag for the base R2DT image, which is useful for pinning specific versions. However, there is no stable tag for the main image, making it difficult to pick a specific version of R2DT as a dependency.

The goal is to setup a GitHub Action that would tag the latest Docker images in both architectures once a new release is created on GitHub.

@anayden Alexey, this is not urgent but you are probably best positioned to do this properly. Thank you in advance for your help! 🐳 🏷