make std::filesystem optional

[UnixY2K]

Description

Add a switch to disable std::filesystem so it can be disabled if required on older compilers, this should let users that older compilers versions to disable it, solving #378 for meson and cmake, additionally checks in the source code if the header is found

changes

• CMakeLists.txt: adds a new option that is disabled by default
• Database.h
  • adds an additional check for <filesystem> and <experimental/filesystem>
  • checks for the previous switch and disables the support if enabled
• meson.build/meson.options adds the same option that disables std::filesystem support

I think this PR should be made on 3.2.1 or greater as is a new feature/enhancement itself and should come with the other planned project cleanups, please let me know if there is anything else required

[UnixY2K]

closed by mistake

[SRombauts]

Thanks!
And yes I agree, this should be released as part of 3.2.1, which I plan to release tomorrow if all goes well.

Sadly, there were no CI/CD checks on this PR, I think because it was closed (or I missed something else?) so I'll have to check status on master post-merge.

Cheers!