This PR is derived from discussion in
ARROW-8790. The current implementation of the Flight RPC exchanges messages using a native endlian format. It does not allow us to exchange data though Flight RPC among different endian machines (e.g. x86_64 <-> s390x).
There is a field to show an endianness at https://github.com/apache/arrow/blob/master/format/Schema.fbs#L343-L346, which is added by