pbx_dundi: Add PJSIP support.

Adds PJSIP as a supported technology to DUNDi.

To facilitate this, we now allow an endpoint to be specified
for outgoing PJSIP calls. We also allow users to force a specific
channel technology for outgoing SIP-protocol calls.

ASTERISK-28109 #close
ASTERISK-28233 #close

Change-Id: I2e28e5a5d007bd49e3df113ad567b011103899bf
(cherry picked from commit b33f92cbb5)

pbx/dundi-parser.c

@@ -236,6 +236,8 @@ static char *proto2str(int proto, char *buf, int bufsiz)
 	case DUNDI_PROTO_H323:
 		strncpy(buf, "H.323", bufsiz - 1);
 		break;
+	case DUNDI_PROTO_PJSIP:
+		strncpy(buf, "PJSIP", bufsiz - 1);
 	default:
 		snprintf(buf, bufsiz, "Unknown Proto(%d)", proto);
 	}