Option needed for Q931_IE_TIME_DATE to be optional in CONNECT message.

The NEC SV8300 rejects the Q931_IE_TIME_DATE for Q.SIG.

Add option to specify if and how much of the current time is put in
Q931_IE_TIME_DATE.
* Send date/time ie never.
* Send date/time ie date only.
* Send date/time ie date and hour.
* Send date/time ie date, hour, and minute.
* Send date/time ie date, hour, minute, and second.
* Send date/time ie default: Libpri will send date and hhmm only when in
NT PTMP mode to support ISDN phones.

(closes issue #19221)
Reported by: kenner

JIRA SWP-3396


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@319427 65c4cc65-6c06-0410-ace0-fbb531ad65f3