Refactor Database and File modules to improve data handling

Update the Database class to include explicit methods for fetching
various entity types, managing relationships, and querying file paths.
Implement hashing logic in the File module to facilitate tracking by
unique identifiers. Add C++20 support in configuration files.

include/File.h

@@ -10,10 +10,12 @@ namespace fs = std::filesystem;
 
 class File {
     public:
-        void importFile( std::string fileName );
+        Track importFile( const std::string& filePath );
         void importFolder( const std::string& folderPath, std::vector<Track>& tracks );
         void readFileTag( Track& t );
         std::string parseFiletype( const std::string& path );
+        void updateLibrary();
+        uint64_t hashString( Track t );
 
     private:
         std::string path_;