Support SHORT or INT16 datatype

OPC quality code standards request 16 bit for each quality code. If I try to store a series of quality codes (each is a 16-bit integer) in iotdb now, I have to specify its data type as INT32, which leaves 16 unused bits, causing a waste of storage. This will be more significant where there is a lot series of quality codes.

I don't know if current compressing method could deal with that. If so, it will be okay to just use INT32.

The issue names no files, tests, or entry points. Start by locating IoTDB's datatype definitions and storage/compression handling for INT32, then determine whether SHORT or INT16 can be supported without wasting storage. Done means 16-bit quality-code series can be stored with an appropriate datatype, or the compression behavior is documented as sufficient.

Written by the indexing model from the issue text.