Add new API call to set a sysctl

REST Request:
-------------------------------
PUT /sysadm/systemmanager
{
   "value" : "0",
   "sysctl" : "security.jail.mount_devfs_allowed",
   "action" : "setsysctl"
}

REST Response:
-------------------------------
{
    "args": {
        "setsysctl": {
            "response": "security.jail.mount_devfs_allowed: 1 -> 0",
            "sysctl": "security.jail.mount_devfs_allowed",
            "value": "0"
        }
    }
}

WebSocket Request:
-------------------------------
{
   "args" : {
      "value" : "0",
      "action" : "setsysctl",
      "sysctl" : "security.jail.mount_devfs_allowed"
   },
   "name" : "systemmanager",
   "namespace" : "sysadm",
   "id" : "fooid"
}

WebSocket Response:
-------------------------------
{
  "args": {
    "setsysctl": {
      "response": "security.jail.mount_devfs_allowed: 1 -> 0",
      "sysctl": "security.jail.mount_devfs_allowed",
      "value": "0"
    }
  },
  "id": "fooid",
  "name": "response",
  "namespace": "sysadm"
}

src/server/WebBackend.cpp

@@ -329,6 +329,10 @@ RestOutputStruct::ExitCode WebSocket::EvaluateSysadmSystemMgmtRequest(const QJso
 	ok = true;
         out->insert("procinfo", sysadm::SysMgmt::procInfo());
       }
+      if(act=="setsysctl"){
+	ok = true;
+        out->insert("setsysctl", sysadm::SysMgmt::setSysctl(in_args.toObject()));
+      }
       if(act=="sysctllist"){
 	ok = true;
         out->insert("sysctllist", sysadm::SysMgmt::sysctlList());

src/server/library/sysadm-systemmanager.cpp

@@ -291,6 +291,27 @@ QJsonObject SysMgmt::procInfo() {
   return retObject;
 }
 
+// Set a sysctl
+QJsonObject SysMgmt::setSysctl(QJsonObject jsin) {
+  QJsonObject retObject;
+
+  QStringList keys = jsin.keys();
+  if (! keys.contains("sysctl") || ! keys.contains("value") ) {
+    retObject.insert("error", "Missing required keys 'sysctl / value'");
+    return retObject;
+  }
+  QString sysctl, value;
+  sysctl = jsin.value("sysctl").toString();
+  value = jsin.value("value").toString();
+  QString output = General::RunCommand("sysctl " + sysctl + "=" + value);
+
+  retObject.insert("sysctl", sysctl);
+  retObject.insert("value", value);
+  retObject.insert("response", output.simplified());
+
+  return retObject;
+}
+
 // Return list of sysctls and their values
 QJsonObject SysMgmt::sysctlList() {
   QJsonObject retObject;

src/server/library/sysadm-systemmanager.h

@@ -21,6 +21,7 @@ public:
 	static QJsonObject killProc(QJsonObject);
 	static QJsonObject memoryStats();
 	static QJsonObject procInfo();
+	static QJsonObject setSysctl(QJsonObject);
 	static QJsonObject sysctlList();
 	static QJsonObject systemInfo();
 };