Add rateCode filter in SearchRQ

Hi there,

I want to be able to filter by rateplancode in the search request. This is specially important for negotiated rates, where I need to be able to indicate which rate/rates I want to receive, and which I do not need.

This way, I can combine and search for any possible combination of rateplan codes as agreed with the supplier, without having to depend on configuration or access code.

Thanks!