logic: source groups for project settings

* project can not have multiple source groups with different types
* language of a project is now inferred from source groups
* setting global NameHierarchy delimiter of first sourceGroup in project
* added project settings migrations for source groups
* Add Settings Migration classes (MoveKey, DeleteKey, Lambda)
* Update sample projects with migrations
* added method to config to retrieve sublevel key names
* implemented recursive removing of keys in settings
* moved project files out of top level
* removed solution parsing code as it is not used anymore

fortune cookie message = The secret of getting ahead is getting started.

src/lib_java/project/SourceGroupJava.h

@@ -0,0 +1,35 @@
+#ifndef SOURCE_GROUP_JAVA_H
+#define SOURCE_GROUP_JAVA_H
+
+#include <memory>
+#include <set>
+
+#include "settings/SourceGroupSettingsJava.h"
+#include "project/SourceGroup.h"
+#include "utility/file/FileManager.h"
+
+class SourceGroupJava: public SourceGroup
+{
+public:
+	SourceGroupJava(std::shared_ptr<SourceGroupSettingsJava> settings);
+	virtual ~SourceGroupJava();
+
+	virtual SourceGroupType getType() const;
+
+	virtual bool prepareIndexing();
+
+	virtual void fetchAllSourceFilePaths();
+
+	virtual std::vector<std::shared_ptr<IndexerCommand>> getIndexerCommands(const bool fullRefresh);
+
+private:
+	bool prepareJavaEnvironment();
+	bool prepareMavenData();
+
+	std::vector<FilePath> getClassPath();
+	std::set<FilePath> fetchRootDirectories();
+
+	std::shared_ptr<SourceGroupSettingsJava> m_settings;
+};
+
+#endif // SOURCE_GROUP_JAVA_H