[TopicUtils] Optimize MangleName(), DemangleName() and MangleType() (backport #788)

[mergify]

🦟 Bug fix

Continuing the improvements in TopicUtils, this patch optimizes MangleName(), DemangleName() and MangleType().

It replaces character-by-character string building with std::replace and adds a missing const reference to avoid copying each string.

The benchmarks show that the new functions (the ones with the 2 suffix improve the original ones).

Summary

Checklist

• Signed all commits for DCO
• Added tests
• Updated documentation (as needed)
• Updated migration guide (as needed)
• Consider updating Python bindings (if the library has them)
• codecheck passed (See contributing)
• All tests passed (See test coverage)
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This is an automatic backport of pull request #788 done by [Mergify](https://mergify.com).

[mergify]

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	both modified:   src/TopicUtils.cc

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