Add maintainer's subcommand to semi-automatically perform a release

This is a cleanup of !386 (closed)

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This merge request basically automates the release process of Axii as much as possible via axii self maintain release.

• Wizard opens armarx_setup/__init__.py for the maintainer to bump the version
• Then, it opens the changelog
• Changelog is auto-generated from the corresponding milestone of the version the maintainer bumped to
• Subcommand will then perform the whole release automatically, including
  • Merging main to stable
  • Re-merging stable into main
  • Updating testing
  • Waiting for all pipelines to pass
  • Pushing the release
  • Two-click auto-generated email with all contributors and inferred co-maintainers
  • Auto-copy-to-clipboard update notification to paste it into Slack immediately

This subcommand automatically commits version bumps and changelog changes, so this MR is a mess commit-wise. I tested it on a fork and it will be squashed here.

Screenshots

Example of the subcommand waiting for the pipeline to succeed:

Example process after triggering the command:

Example fully auto-generated email after one click: