Upgrade codebase to C++ 20 + fix warnings + update submodules (#6115)

src/common/hash.h

@@ -33,6 +33,14 @@ static inline u64 ComputeStructHash64(const T& data) noexcept {
     return ComputeHash64(&data, sizeof(data));
 }
 
+/**
+ * Combines the seed parameter with the provided hash, producing a new unique hash
+ * Implementation from: http://boost.sourceforge.net/doc/html/boost/hash_combine.html
+ */
+inline u64 HashCombine(std::size_t& seed, const u64 hash) {
+    return seed ^= hash + 0x9e3779b9 + (seed << 6) + (seed >> 2);
+}
+
 /// A helper template that ensures the padding in a struct is initialized by memsetting to 0.
 template <typename T>
 struct HashableStruct {