Creates a new callback for a specified connector, such as a SalesforceOauth2 connector, or a Microsoft CRM connector.
Accepted values for Origin:
 dynamics
 sharepoint
 dynamics2011
 dynamics2013
 dynamics2015
 sharepoint2010
 sharepoint2013
 salesforceOauth2
 Note that, when using the origin "salesforceOauth2", the key field of the Callback object has a specific format.
 The base64 encoded string for the following JSON structure is expected in the key field.
 {
    host: [salesforce oauth host],
    client_id: [salesforce connected app client id]
    refresh_token: [salesforce connected app refresh token],
 }
 This is an example of a valid JSON structure for the key field:
 {
   host: [salesforce oauth host],
   client_id: [salesforce connected app client id]
   refresh_token: [salesforce connected app refresh token],
 }
 The base64 encoded string for the JSON example above would be (disregarding linebreaks):
 [base64 encoded string for the JSON structure above]
post https://rls.congacloud.com/api/sign/v1/cs-callback/connectors/
