Make use of c++20 features

[ptheywood]

After #1302 is merged, we can make use of c++ features througout FLAMEGPU, both in new code and replacing alternatives in existing code.

This could include:

• <format> for modern string formatting (much faster than std::ostringstream)
• <ranges>
• <span>
• <source_location>
• constinit/consteval

This issue can be closed at any point rather than waiting for exhaustive adoption of c++20 features (but format and source_location would be nice to use where appropriate), or split into sub-issues.