WIP: Upgrade fmt from 8.1.1 to 11.0.2

[sepeth]

And, added via cmake FetchContent, and removed contrib/fmt-8.1.1

Please don't merge this yet. Because I see CycleTest is failing when I run Simulation with tests/default.txt due to Rate below desired rate. I saw transactions metrics has dropped after this change (tested only on macOS). Apparently there was a performance regression with 11, but it says it got fixed with 11.0.2 and it seems unrelated (see 11.0.2 Release Notes).

I wanted to share this PR in case it is useful in the future and if someone has an idea.

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