Network: Add Q_GADGET to types exposed in signals and slots

In order to build a complete graph of metaobjects via properties and
methods we need to know about all argument and return types as
metaobjecs. Such a graph is desirable for reasoning about the
consistency of the type system.

Task-number: QTBUG-101143
Change-Id: Ic4e2f58a4275df06178437c6d45270f3f2aa5ce6
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>

src/network/kernel/qauthenticator.h

@@ -16,6 +16,7 @@ class QUrl;
 
 class Q_NETWORK_EXPORT QAuthenticator
 {
+    Q_GADGET
 public:
     QAuthenticator();
     ~QAuthenticator();

src/network/kernel/qhostinfo.h

@@ -17,6 +17,7 @@ class QHostInfoPrivate;
 
 class Q_NETWORK_EXPORT QHostInfo
 {
+    Q_GADGET
 public:
     enum HostInfoError {
         NoError,

src/network/kernel/qnetworkproxy.h

@@ -77,6 +77,7 @@ class QNetworkProxyPrivate;
 
 class Q_NETWORK_EXPORT QNetworkProxy
 {
+    Q_GADGET
 public:
     enum ProxyType {
         DefaultProxy,

src/network/ssl/qsslpresharedkeyauthenticator.h

@@ -16,6 +16,7 @@ QT_BEGIN_NAMESPACE
 class QSslPreSharedKeyAuthenticatorPrivate;
 class QSslPreSharedKeyAuthenticator
 {
+    Q_GADGET_EXPORT(Q_NETWORK_EXPORT)
 public:
     Q_NETWORK_EXPORT QSslPreSharedKeyAuthenticator();
     Q_NETWORK_EXPORT ~QSslPreSharedKeyAuthenticator();