Replace not-fully-initializing DTO constructors

There were some constructors in the DTOs which allowed construction of
DTO which weren't fully initialized. These constructors have been made
private, as they are still used in the 'fromJson' methods. Additionally,
a constructor with all required parameters to fully initialize the
class has been added.

Additionally, the Loader class has been modified, since it no longer can
assume it is able to default construct the parameter type. The parameter
is now stored as an optional.

Closes #15

core/include/JellyfinQt/dto/serverconfiguration.h

@@ -56,7 +56,63 @@ namespace DTO {
 
 class ServerConfiguration {
 public:
-	ServerConfiguration();
+	ServerConfiguration(	
+		qint32 logFileRetentionDays,			
+		bool isStartupWizardCompleted,					
+		QSharedPointer<Version> previousVersion,					
+		bool enableUPnP,			
+		bool enableMetrics,			
+		qint32 publicPort,			
+		bool uPnPCreateHttpPortMap,					
+		bool enableIPV6,			
+		bool enableIPV4,			
+		bool enableSSDPTracing,					
+		qint32 uDPSendCount,			
+		qint32 uDPSendDelay,			
+		bool ignoreVirtualInterfaces,					
+		qint32 gatewayMonitorPeriod,			
+		bool enableMultiSocketBinding,			
+		bool trustAllIP6Interfaces,							
+		bool autoDiscoveryTracing,			
+		bool autoDiscovery,			
+		qint32 publicHttpsPort,			
+		qint32 httpServerPortNumber,			
+		qint32 httpsPortNumber,			
+		bool enableHttps,			
+		bool enableNormalizedItemByNameIds,							
+		bool isPortAuthorized,			
+		bool quickConnectAvailable,			
+		bool enableRemoteAccess,			
+		bool enableCaseSensitiveItemIds,			
+		bool disableLiveTvChannelUserDataName,																	
+		qint32 minResumePct,			
+		qint32 maxResumePct,			
+		qint32 minResumeDurationSeconds,			
+		qint32 minAudiobookResume,			
+		qint32 maxAudiobookResume,			
+		qint32 libraryMonitorDelay,			
+		bool enableDashboardResponseCaching,			
+		ImageSavingConvention imageSavingConvention,					
+		bool skipDeserializationForBasicTypes,									
+		bool saveMetadataHidden,					
+		qint32 remoteClientBitrateLimit,			
+		bool enableFolderView,			
+		bool enableGroupingIntoCollections,			
+		bool displaySpecialsWithinSeasons,											
+		bool enableExternalContentInSuggestions,			
+		bool requireHttps,			
+		bool enableNewOmdbSupport,					
+		bool isRemoteIPFilterBlacklist,			
+		qint32 imageExtractionTimeoutMs,					
+		bool enableSimpleArtistDetection,					
+		bool enableSlowResponseWarning,			
+		qint64 slowResponseThresholdMs,									
+		qint32 libraryScanFanoutConcurrency,			
+		qint32 libraryMetadataRefreshConcurrency,			
+		bool removeOldPlugins,			
+		bool disablePluginImages		
+	);
+
 	ServerConfiguration(const ServerConfiguration &other);
 	
 	/**
@@ -901,8 +957,13 @@ protected:
 	qint32 m_libraryMetadataRefreshConcurrency;
 	bool m_removeOldPlugins;
 	bool m_disablePluginImages;
+
+private:
+	// Private constructor which generates an invalid object, for use withing ServerConfiguration::fromJson();
+	ServerConfiguration();
 };
 
+
 } // NS DTO
 
 namespace Support {