AK: Implement SipHash as the default hash algorithm for most use cases

SipHash is highly HashDoS-resistent, initialized with a random seed at
startup (i.e. non-deterministic) and usable for security-critical use
cases with large enough parameters. We just use it because it's
reasonably secure with parameters 1-3 while having excellent properties
and not being significantly slower than before.

Kernel/CMakeLists.txt

@@ -522,6 +522,7 @@ set(AK_SOURCES
     ../AK/GenericLexer.cpp
     ../AK/Hex.cpp
     ../AK/MemoryStream.cpp
+    ../AK/SipHash.cpp
     ../AK/Stream.cpp
     ../AK/StringBuilder.cpp
     ../AK/StringUtils.cpp