Improve support of parameters in OperationChains

When operationChains are called, parameters that may have been passed to the automation call will be lost.
To avoid this we should integrate the parameter map to the context map in case of OperationChains calls.

In addition, since automation calls are marshaled using JSON, it could be useful to be able to read JSON structures in context and paramter (i.e. don't for conversion to String).