Add support for return to sender

[thibmaek]

"processOverview": {
"activeStepTextKey": "RETOUR_DELIVERED",
"textKey": "step.text.retour.delivered",
"alert": false,
"processSteps": [
{
"name": "return_to_sender",
"status": "completed",
"label": {
"main": "returnToSender"
},
"knownProcessStep": "RETURN_TO_SENDER"
},
{
"name": "processing",
"status": "completed",
"label": {
"main": "processing",
"detail": "byBpost"
},
"knownProcessStep": "PROCESSING"
},
{
"name": "out_for_delivery",
"status": "completed",
"label": {
"main": "onTheWay",
"detail": "towardsSender"
},
"knownProcessStep": "ON_THE_WAY_TO_SENDER"
},
{
"name": "delivered",
"status": "active",
"label": {
"main": "returned",
"detail": "toSender"
},
"knownProcessStep": "DELIVERED_TO_SENDER"
}
]