Add couchdb index management capabilities to the state database layer.

Add create and delete index functions to statecouchdb.

Add HandleChaincodeDefinition to statecouchdb.

Add unit tests for create and save index functions.

Add unit tests for HandleChaincodeDefinition.

Change-Id: I82f31ced8eb666e607c549f995d0c83fc7364664
Signed-off-by: Chris Elder <chris.elder@us.ibm.com>