[FeatureRequest] Add convenience procs to check if a formparam/queryparam exists
Right now, prologue has getQueryParam / getPathParam / getPostParam / getFormParam.
However, for my own usecases I have scenarios where the same controller handles multiple possible URLs / form input possibilities and I'd like to be able to just check whether a given request *has* a specific form param/pathParam/queryParam etc.

So convenience procs like "hasQueryParam" etc. would be very useful to me. Would it be desired to add such procs to prologue? Alternatively, the same could be achieved by having the "get" procs above return Option types, to symbolize that a given param might not exist.