Everywhere: Use AK/Math.h if applicable

AK's version should see better inlining behaviors, than the LibM one.
We avoid mixed usage for now though.

Also clean up some stale math includes and improper floatingpoint usage.

Userland/Utilities/ntpquery.cpp

@@ -292,7 +292,7 @@ int main(int argc, char** argv)
     NtpTimestamp T3 = transmit_timestamp;
     NtpTimestamp T4 = destination_timestamp;
     auto timestamp_difference_in_seconds = [](NtpTimestamp from, NtpTimestamp to) {
-        return static_cast<int64_t>(to - from) / pow(2.0, 32);
+        return static_cast<i64>(to - from) >> 32;
     };
 
     // The network round-trip time of the request.