feat: std::format support for dpp::snowflake

[ruslan-ilesik]

This pr adds std::format support for dpp::snowflake, if we do not have c++20 or have no include for it will be automatically disabled for compilation.

Test case was implemented to check formatting.

Code change checklist

• I have ensured that all methods and functions are fully documented using doxygen style comments.
• My code follows the coding style guide.
• I tested that my change works before raising the PR.
• I have ensured that I did not break any existing API calls.
• I have not built my pull request using AI, a static analysis tool or similar without any human oversight.

[netlify]

✅ Deploy Preview for dpp-dev ready!

Name	Link
🔨 Latest commit	bc01f2f
🔍 Latest deploy log	https://app.netlify.com/sites/dpp-dev/deploys/66af6403ef8ab6000889141f
😎 Deploy Preview	https://deploy-preview-1203--dpp-dev.netlify.app
📱 Preview on mobile	Toggle QR Code... Use your smartphone camera to open QR code link.

---

To edit notification comments on pull requests, go to your Netlify site configuration.

[Henonicks]

tested this on Windows and got
snowflake: std::format support PASS
at the end

[ruslan-ilesik]

So with last commit i have introduced usage of Cmake feature called configure_file which allows us autogenerate headers with some definitions when build dpp, this way we can remove need to define DPP_HAS_FORMAT as it will be defined in it when compiling it.

In theory same way we can eliminate need to specify -DDPP_CORO when compiling bot with dpp with coro enabled in lib.

[braindigitalis]

theres a massive problem with this!
If cmake detects that C++20 is available it will always enable std::format. This means the user is forced to use -std=c++20 for all their bots, even where they dont want to use C++20. This fundamentally breaks compatibility.
Nothing tells the user they must use C++20 anywhere, and furthermore, if they have a need for C++17 they simply cannot ever use C++17 any more.

[ruslan-ilesik]

If lib is build with c++20 then ye, bots will be required to use c++20, I can easily fix it by wrapping cmake define into check of c++ version.

[Jaskowicz1]

I'm happy with it but need to see what @braindigitalis thinks about the autoconfig.h idea.

[ruslan-ilesik]

I have tested changes locally on my wsl2 (ubuntu) and tests passed, also compiling bot with -DPP_FORMATTERS and without had required behavior