refactor: Improve ordering of headers with clang-format (#5343)

Removes all manual header groupings from source and header files by leveraging clang-format options.

examples/example/src/example.cpp

@@ -1,7 +1,7 @@
-#include <cstdio>
-
 #include <xrpl/protocol/BuildInfo.h>
 
+#include <cstdio>
+
 int main(int argc, char const** argv) {
     std::printf("%s\n", ripple::BuildInfo::getVersionString().c_str());
     return 0;