Provide default Renovate regex managers

Across various projects in this org, it would be good if the engineers have the option to manage versions outside files natively supported by Renovate.

One recent instance I came across was the Ramalama maintainers wanted to pin whisper.cpp to a specific git hash https://github.com/containers/ramalama/pull/49, however having that version follow the main branch. For now, he has hardcoded the commit hash, and I assume will manually update it as and when the maintainers remember.

With this change, the Ramalama maintainers can simply change the configuration to store the Git commit sha as an ARG or ENV, and add a small portion of metadata above the declaration.