LibCompress: Turn the DEFLATE implementation into a stream.

Previously, the implementation would produce one Vector<u8> which
would contain the whole decompressed data. That can be a lot and
even exhaust memory.

With these changes it is still necessary to store the whole input data
in one piece (I am working on this next,) but the output can be read
block by block. (That's not optimal either because blocks can be
arbitrarily large, but it's good for now.)

Libraries/LibCompress/Zlib.h

@@ -49,4 +49,5 @@ private:
     ReadonlyBytes m_input_data;
     ReadonlyBytes m_data_bytes;
 };
+
 }