Fix .dll installation directory on Windows

[traversaro]

🦟 Bug fix

Fix .dll installation directory on Windows .

Summary

On Windows, .dll libraries are tipically installed in <prefix>/bin, while before this fix, the .dll libraries were installed by this project in <prefix>/lib, resulting the warning:

Library error: ignition-tools-backward.dll not found. Improved backtrace generation will be disabled

When the ign command was used, as ignition-tools-backward.dll was not found in the directory in which ruby's function to find dll libraries was looking into.

Checklist

• [ ] Signed all commits for DCO
• [ ] Added tests
• [ ] Updated documentation (as needed)
• [ ] Updated migration guide (as needed)
• [ ] codecheck passed (See contributing)
• [ ] All tests passed (See test coverage)
• [ ] While waiting for a review on your PR, please help review another open pull request to support the maintainers

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