Fix: signal/slot macro -> func pointer & network fixes

- convert qt connect calls to use function pointers instead of the signal/slot macros wherever practical (UI classes were mostly left alone, target was tasks and processes)
- give signals an explicit receivers to use the static method over the instance method wherever practical
- ensure networks tasks are using the `errorOccured` signal added in Qt5.15 over the deprecated `error` signal
- ensure all networks tasks have an sslErrors signal connected
- add seemingly missing `MinecraftAccount::authSucceeded` connection for `MSAInteractive` login flow

Signed-off-by: Rachel Powers <508861+Ryex@users.noreply.github.com>

launcher/net/NetAction.h

@@ -61,6 +61,17 @@ class NetAction : public Task {
     virtual void downloadFinished() = 0;
     virtual void downloadReadyRead() = 0;
 
+    virtual void sslErrors(const QList<QSslError>& errors) {
+        int i = 1;
+        for (auto error : errors) {
+            qCritical() << "Network SSL Error #" << i << " : " << error.errorString();
+            auto cert = error.certificate();
+            qCritical() << "Certificate in question:\n" << cert.toText();
+            i++;
+        }
+
+    };
+
    public slots:
     void startAction(shared_qobject_ptr<QNetworkAccessManager> network)
     {