Replace input validation of url params by generic validation method

[remkohdev]

Currently, e.g. in histohour.js, input validation is implemented for each param, required and optional, with a lot of repetitive code:

// optional fields
// extraParams
if(msg.params && msg.params.extraParams){
urlParams.push("extraParams="+msg.params.extraParams);
}else{
if(node.extraParams || node.extraParams!=""){
urlParams.push("extraParams="+ node.extraParams);
}
}
// sign
if(msg.params && msg.params.sign){
urlParams.push("sign="+msg.params.sign);
}else{
if(node.sign || node.sign!=""){
urlParams.push("sign="+ node.sign);
}
}

This should be replaced by a generic method, to which you pass: the full input object and with a params setting or config object, the method should validate if input object complies to paramsConfig object.