Add support for specifying ParrotRequest body as a ByteArrayInputStream

[cahlbin]

This allows sending parrot requests with a body that are to be interpreted as Content-Type: application/octet-stream.

The choice of requiring a ByteArrayInputStream vs any InputStream was simply because it made the allocation of the ChannelBuffer simple, because then InputStream.available() can be used reliably, and in favor over more complex allocation/copying of the InputStream to a Netty ChannelBuffer.

[CLAassistant]

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