[NEW] Add twilio whatsapp template custom fields

[bhardwajaditya]

Closes: WideChat/Rocket.Chat#1385

Sample CX custom payload:

{
"customFields": {
"contentSid": "HXeb7f68d72e40185a3a64f649348e5f69",
"messagingServiceSid": "xxxxxxxxxxx", #RC will populate
"contentVariables": {
"1": "Aditya"
}
}
}

[ear-dev]

@bhardwajaditya Does Rocketchat or the Dialogflow.app keep track of the messageServiceSid? I'm not sure if the CX agent has that info.... looking into it, but I doubt it.
It might be the case that if RC receives a customPayload for this use-case, RC might have to fill in the messageServiceSid. Is that possible?

[ear-dev]

DESIGN:

• When receiving messages from twilio, grab the messageServiceSID and put it in an RC customField in the room db entry.
• When sending template messages in the twilio integration, grab the msSID from the custom field and finish populating the customField from the CX.agent.