Functions for email-campaigns endpoints

[dynata-bradley]

http://petstore.swagger.io/?url=https://kaleidoscope-survey-api.cmix.com/swagger.json#/

• POST
  ​/projects​/{projectId}​/email-campaigns
  Create Campaign
• GET
  ​/projects​/{projectId}​/email-campaigns
  Get Email Campaign List
• GET
  ​/projects​/{projectId}​/email-campaigns​/{emailCampaignId}
  Get Single Project Campaign
• DELETE
  ​/projects​/{projectId}​/email-campaigns​/{emailCampaignId}
  Delete Email Campaign
• PATCH
  ​/projects​/{projectId}​/email-campaigns​/{emailCampaignId}
  Update Email Campaign