* write cdrs and alerts with service_provider_sid
* update to latest @jambonz/http-authenticator which sends sip headers
* add call_sid to cdr when call is connected
* write call counts by SP as well as account, bugfix to allow digit '0' in dtmf-relay
* support for sip refer to transfer an incoming call
* when sending REFER for call transfer, format Refer-To with carrier trunk if applicable
* better handling of e164 on Refer-To header