Allow providing an initial value for AggregateSensor and SysFsSensor

To be able to use initialValue from SensorProperty.

systemstats/AggregateSensor.cpp

@@ -75,7 +75,12 @@ public:
 };
 
 AggregateSensor::AggregateSensor(SensorObject *provider, const QString &id, const QString &name)
-    : SensorProperty(id, name, provider)
+    : AggregateSensor(provider, id, name, QVariant{})
+{
+}
+
+AggregateSensor::AggregateSensor(SensorObject *provider, const QString &id, const QString &name, const QVariant &initialValue)
+    : SensorProperty(id, name, initialValue, provider)
     , d(std::make_unique<Private>())
 {
     d->subsystem = qobject_cast<SensorContainer *>(provider->parent());

systemstats/AggregateSensor.h

@@ -31,6 +31,7 @@ class SYSTEMSTATS_EXPORT AggregateSensor : public SensorProperty
 
 public:
     AggregateSensor(SensorObject *provider, const QString &id, const QString &name);
+    AggregateSensor(SensorObject *provider, const QString &id, const QString &name, const QVariant &initialValue);
     ~AggregateSensor() override;
 
     QVariant value() const override;

systemstats/SysFsSensor.cpp

@@ -18,7 +18,12 @@ public:
 };
 
 SysFsSensor::SysFsSensor(const QString &id, const QString &path, SensorObject *parent)
-    : SensorProperty(id, parent)
+    : SysFsSensor(id, path, QVariant{}, parent)
+{
+}
+
+SysFsSensor::SysFsSensor(const QString &id, const QString &path, const QVariant &initialValue, SensorObject *parent)
+    : SensorProperty(id, id, initialValue, parent)
     , d(std::make_unique<Private>())
 {
     d->path = path;

systemstats/SysFsSensor.h

@@ -24,6 +24,7 @@ class SYSTEMSTATS_EXPORT SysFsSensor : public SensorProperty
 
 public:
     SysFsSensor(const QString &id, const QString &path, SensorObject *parent);
+    SysFsSensor(const QString &id, const QString &path, const QVariant &initialValue, SensorObject *parent);
     ~SysFsSensor() override;
 
     /**