Add libunwind into the container

[DL6ER]

What does this implement/fix?

Add libunwind into the container. The primary goal of libunwind is to define a portable and efficient C programming interface (API) to determine the call-chain of a program to restore the ability to generate callbacks on application crashes. We "lost" this ability when switching to musl-based build environments.

Related issue or feature (if applicable): N/A

Pull request in docs with documentation (if applicable): N/A

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• The code change is tested and works locally.
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[DL6ER]

Superseded by #83