Add benchmark for hex string conversion performance

[puji4810]

• Introduced a new benchmark file atoi_vs_from_chars_hex.cc to compare the performance of various hex string conversion methods, including strtoul, std::from_chars, fast_io::char_digit_to_literal, and fast_float::from_chars.
• Updated CMakeLists.txt to include the new benchmark executable benchmark.0022.from_chars_hex and set appropriate include directories and compile features.