internal release process: publishing to DockerHub

Comment from @Benjamin-Loison

> Concerning PyPI and DockerHub, as matrix-commander Python compilation (and DockerHub I guess) is ridiculous in terms of time, contrarily to matrix-commander-rs, for Python I like working with correct commits, that is people just use last commit state. What is your opinion about it? Should we still release PyPI and DockerHub releases? I will wait your answer to figure out how I should proceed, possibly only with https://crates.io/.

> For reference: https://github.com/8go/matrix-commander/pull/218#issuecomment-4716901272 seems to be a blocker anyway, as [8go/matrix-commander/settings/secrets/actions](https://github.com/8go/matrix-commander/settings/secrets/actions) mentions Docker and PyPI too. [8go/matrix-commander-rs/settings/secrets/actions](https://github.com/8go/matrix-commander-rs/settings/secrets/actions) is empty.

Regarding DockerHub: I have no personal use for DockerHub. I am also not downloading, running images from DockerHub. So, whatever gets published there I would never test it. It is acceptable to me to remove DockerHub from the release process.

What speaks in favor: it should be automatic, a Github action that causes little human work.

Look at the existing GitHub Actions workflows in .github/workflows/ to understand the current release process. Identify the steps that publish to DockerHub and PyPI. The discussion references secrets in the repository settings; check what secrets are configured. The goal is to update the release documentation and possibly the automation to remove DockerHub publishing, ensuring the process still works for PyPI and crates.io.

Scritto dal modello di indicizzazione a partire dal testo della issue.