Create new scripts for bumping versions and aliases

[j-rivero]

Context

Coming from #3289 (comment)

Answering @scpeters comment on "if we prefer 10 lines of bash or scripts", this is my personal take nowadays: given how fast we can use AI to produce, review and evolve trivial helper tools it is now my feeling that they are usually more complete, less error-prone in corner cases and not difficult to test or manually review. So I'm inclined for produce and use them. This does not mean that we can fall into errors, over-confidence or black-box-quick-testing but given the results that I see today, I think that worth the effort to give this approach a try.

Technical changes in the PR

This pull request introduces a new unified tool for managing Homebrew aliases in the Gazebo tap. It adds a Python script, manage_aliases.py, along with documentation in scripts/README.md. The script automates the creation of versioned and collection-scoped aliases:

New alias management tooling:

• Added scripts/manage_aliases.py, a Python script providing two main subcommands:
  • bump: Automatically creates next-major-version aliases for all discovered gz-* and sdformat* libraries, supporting dry-run and targeted library selection. It also auto-discovers libraries and corrects broken or outdated symlinks.
  • collection-aliases: Generates collection-scoped aliases for each dependency of a specified collection formula (e.g., gz-jetty-cmake), with support for dry-run and automatic parsing of dependencies.

Documentation:

• Added detailed usage instructions and behavioral notes for manage_aliases.py to scripts/README.md, including subcommand explanations, example invocations, and descriptions of key features.