T6934: Add preshared key for zabbix-agent monitoring service

- Allow configure preshared key for zabbix-agent
- Added op mode command for generatre random psk secret
- Removed duplicate xml definition for psk settings


Configure authentication mode:
```
# set service monitoring zabbix-agent authentication mode
Possible completions:
   pre-shared-secret    Use a pre-shared secret key
```

Configure PSK Settings:
```
# set service monitoring zabbix-agent authentication psk
Possible completions:
   id                   ID for authentication
   secret               pre-shared secret key

```

Generate Random PSK:
```
$ generate psk random
Possible completions:
  <Enter>               Execute the current command
  size                  Key size in bytes

```

1 files changed, 2 insertions, 21 deletions

diff --git a/interface-definitions/include/stunnel/psk.xml.i b/interface-definitions/include/stunnel/psk.xml.i
index db11a93d3..a8226c866 100644
--- a/interface-definitions/include/stunnel/psk.xml.i
+++ b/interface-definitions/include/stunnel/psk.xml.i
@@ -4,27 +4,8 @@
     <help>Pre-shared key name</help>
   </properties>
   <children>
-    <leafNode name="id">
-      <properties>
-        <help>ID for authentication</help>
-        <valueHelp>
-          <format>txt</format>
-          <description>ID used for authentication</description>
-        </valueHelp>
-      </properties>
-    </leafNode>
-    <leafNode name="secret">
-      <properties>
-        <help>pre-shared secret key</help>
-        <valueHelp>
-          <format>txt</format>
-          <description>pre-shared secret key are required to be at least 16 bytes long, which implies at least 32 characters for hexadecimal key</description>
-        </valueHelp>
-        <constraint>
-          <validator name="psk-secret"/>
-        </constraint>
-      </properties>
-    </leafNode>
+    #include <include/auth-psk-id.xml.i>
+    #include <include/auth-psk-secret.xml.i>
   </children>
 </tagNode>
 <!-- include end -->