[FAB-8026] configtxlator cli compute update
[FAB-8026] configtxlator cli compute update

Presently, configtxlator only exposes its functions through a REST API.
This is convenient for cross-language compatibility, but it forces CLI
users to fall back to writing CURL commands.  This CR simply exposes the
update computation logic directly via the CLI.

Change-Id: Ifc5e7e33d0a9cb43d181a3c77843d41827938397
Signed-off-by: Jason Yellick <3a1724207862302656e55e6f840a9996dad69e59@us.ibm.com>

xixuejia/fabric,binhn/fabric,stemlending/fabric,manish-sethi/fabric-sidedb,manish-sethi/fabric-sidedb,stemlending/fabric,binhn/fabric,manish-sethi/fabric-sidedb,muralisrini/fabric,hyperledger/fabric,manish-sethi/fabric,manish-sethi/fabric-sidedb,jimthematrix/fabric,xixuejia/fabric,muralisrini/fabric,manish-sethi/fabric-sidedb,manish-sethi/fabric-sidedb,stemlending/fabric,binhn/fabric,manish-sethi/fabric,jimthematrix/fabric,muralisrini/fabric,xixuejia/fabric,manish-sethi/fabric-sidedb,hyperledger/fabric,stemlending/fabric