Add basic character device support. Start with null and zero.

VirtualFileSystem/ZeroDevice.cpp

@@ -0,0 +1,27 @@
+#include "ZeroDevice.h"
+#include "Limits.h"
+#include <AK/StdLib.h>
+#include <cstring>
+#include <cstdio>
+
+ZeroDevice::ZeroDevice()
+{
+}
+
+ZeroDevice::~ZeroDevice()
+{
+}
+
+ssize_t ZeroDevice::read(byte* buffer, size_t bufferSize)
+{
+    printf("read from zero device\n");
+    size_t count = min(GoodBufferSize, bufferSize);
+    memset(buffer, 0, count);
+    return count;
+}
+
+ssize_t ZeroDevice::write(const byte*, size_t bufferSize)
+{
+    return min(GoodBufferSize, bufferSize);
+}
+