Add option for MESSAGE-MAgPIE connection

[ywpratama]

Required: TBA
Commits history is mixed with commits not intended to be included in this draft pull request.
The list of what were done includes:

1. Create a draft pull request for the project/justmip_rebase_magpie branch
2. Rebase the draft PR against main
3. Resolve conflicts
4. Force push the rebase to the branch
5. Together with Paul, rebasing and cleaning up the branch to exclude unwanted commits
   • The branch history is now cleaned up
6. Yoga is currently identifying changes made to GAMS code and analysing potential approaches to add option to MAgPIE connection

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PR checklist

• Continuous integration checks all ✅
• Add or expand tests; coverage checks both ✅
• Add, expand, or update documentation.
• Update release notes.

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