[C++] C++20: add/use concepts

[pitrou]

Describe the enhancement requested

We should investigate the use of C++20 concepts to ease writing type-specific Arrow code that is currently relying on SFINAE or other tricks.

Component(s)

C++

[goldigd05]

Hi, I would like to explore using C++20 concepts in Arrow C++.

Currently, many template functions rely on SFINAE or type traits to enforce type constraints,
which can be complex and hard to maintain. I propose prototyping a few functions with
C++20 concepts to simplify type-specific code, improve readability, and provide clearer
compiler diagnostics.

I am happy to submit a small prototype PR for review.

[pitrou]

@goldigd05 Hey, yes, you start with a prototype PR to make sure we're on the same line. Looking forward to review your contribution!