Consistent Integer Types

example of using, to avoid mixed usage of std::uint/std::int and uint/int...
```cpp
using u64 = std::uint64_t;
using u32 = std::uint32_t;
using u16 = std::uint16_t;
using u8  = std::uint8_t;

using i64 = std::int64_t;
using i32 = std::int32_t;
using i16 = std::int16_t;
using i8  = std::int8_t;

using usize = std::size_t;
using isize = std::ptrdiff_t;

#if defined(__GNUC__) && defined(IS_64BIT)
__extension__ using u128 = unsigned __int128;
__extension__ using i128 = signed __int128;
#endif
```

closes https://github.com/official-stockfish/Stockfish/pull/6874

No functional change

src/nnue/nnue_misc.cpp

@@ -28,6 +28,7 @@
 #include <sstream>
 
 #include "../position.h"
+#include "../misc.h"
 #include "../types.h"
 #include "../uci.h"
 #include "network.h"
@@ -71,7 +72,7 @@ trace(Position& pos, const Eval::NNUE::Network& network, Eval::NNUE::Accumulator
        << "|            |   (PSQT)   |  (Layers)  |            |\n"
        << "+------------+------------+------------+------------+\n";
 
-    for (std::size_t bucket = 0; bucket < LayerStacks; ++bucket)
+    for (usize bucket = 0; bucket < LayerStacks; ++bucket)
     {
         ss << "|  " << bucket << "        "  //
            << " |  ";