Migrate tooling config to tool-versions

What does this merge request do and why?

The tooling updates are not automated by Renovate Bot since .rtx.toml is not supported.

This change allows Renovate Bot to automate the dependency update by moving the config from .rtx.toml to .tool-versions. rtx/mise can read both .rtx.toml and .tool-versions.

I have also update references of rtx to mise (https://mise.jdx.dev/).

How to set up and validate locally

To migrate to mise (formally named rtx), please follow the instructions laid out in the official doc.

Merge request checklist

• I've ran the affected pipeline(s) to validate that nothing is broken.
• Tests added for new functionality. If not, please raise an issue to follow up.
• Documentation added/updated, if needed.