Changes to Add an OAuth app

added the new optional request property metaAppId

added the new optional request property metaAppSecret

added the new optional request property slackSigningSecret

added the optional property app/hasSlackSigningSecret to the response with the 201 status

added the optional property app/slackEvents to the response with the 201 status

added the optional property app/sharedWebhookUrl to the response with the 201 status

removed the enum value ads of the request property scopeAreas/items

added the optional property app/webhook to the response with the 201 status

removed the ads enum value from the app/scopeAreas/items response property for the response status 201

endpoint added