Route for the revenue

[JulesGresset]

Description
the route kpi/revenues with query param timeBegin and timeEnd return the sum of every orders payed.
The breakdown param group the revenues base on their time (see explications of breakdown in #173)
Is the param useCase is equal to statsPOS, the route should also return the number of orders and the average waiting time (both of this should also be grouped if the breakdown is used !)

Example
timeBegin: 00:00
timeEnd: 00:30
breakdown: 15
useCase: statsPOS

{
    "00:00": {
        "revenues": Revenues between 00:00 and 00:15,
        "ordersCount": Nbr of orders between 00:00 and 00:15,
        "averageWaitingTime": Avg wait time between 00:00 and 00:15
    },
    "00:15": {
        "revenues": Revenues between 00:15 and 00:30,
        "ordersCount": Nbr of orders between 00:15 and 00:30,
        "averageWaitingTime": Avg wait time between 00:15 and 00:30
    },
}