ci: remove unused ci packaging script

[ClementTsang]

Description

A description of the change, what it does, and why it was made. If relevant (such as any change that modifies the UI), please provide screenshots of the changes:

I think this used to be used for AUR packaging. We don't do that anymore so we can remove this, I don't see it used anywhere.

Issue

If applicable, what issue does this address?

Closes: #

Testing

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If this is a code change, please also indicate which platforms were tested:

• Windows
• macOS
• Linux

Checklist

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• Areas your change affects have been linted using rustfmt (cargo fmt)
• The change has been tested and doesn't appear to cause any unintended breakage
• Documentation has been added/updated if needed (README.md, help menu, doc pages, etc.)
• The pull request passes the provided CI pipeline
• There are no merge conflicts
• If relevant, new tests were added (don't worry too much about coverage)