Add xcat marker in goconserver configuration file

[chenglch]

Previously, it is impossible to know if the goconerver is started
by xcat. This patch add a marker in /etc/goconserver/server.conf
to help check the status. In addition, use server-cred.pem instead
of server-key.pem as it is not exist on SN.

This patch also control the service status of goconserver and conserver
when restarting the xcatd service on service node.

implement: #4542

[root@sn02 ~]# chdef sn02 setupconserver=1
1 object definitions have been created or modified.
[root@sn02 ~]# service xcatd restart
Restarting xcatd (via systemctl):                          [  OK  ]
[root@sn02 ~]# ps -ef | grep conserver
root      27679      1  0 02:26 ?        00:00:00 /usr/sbin/conserver -o -O1 -d
root      27680  27679  0 02:26 ?        00:00:00 /usr/sbin/conserver -o -O1 -d
root      27756  26188  0 02:26 pts/1    00:00:00 grep --color=auto conserver
[root@sn02 ~]# chdef sn02 setupconserver=2
1 object definitions have been created or modified.
[root@sn02 ~]# service xcatd restart
Restarting xcatd (via systemctl):                          [  OK  ]
[root@sn02 ~]#
[root@sn02 ~]#
[root@sn02 ~]#
[root@sn02 ~]# ps -ef | grep conserver
root      27885      1  0 02:26 ?        00:00:00 /usr/bin/goconserver
root      27986  26188  0 02:33 pts/1    00:00:00 grep --color=auto conserver

[xcatbot]

CI CHECK RESULT : > PR FORMAT CORRECT> BUILD SUCCESSFUL > INSTALL XCAT SUCCESSFUL> CODE SYNTAX CORRECT> FAST REGRESSION TEST Successful: Totalcase 215 Pass 215 failed 0

[zet809]

Looks good to me, I agree to merge. Thx, @chenglch