Added song delete endpoint

include/database/coverArtRepository.h

@@ -14,6 +14,7 @@ public:
 
     Cover retrieveRecord(Cover&, coverFilter);
 
+    void deleteRecord(const Cover&);
     void saveRecord(const Cover&);
 private:
     Cover parseRecord(MYSQL_RES*);

include/database/songRepository.h

@@ -19,6 +19,7 @@ public:
 
     Song retrieveRecord(Song&, songFilter);
 
+    void deleteRecord(const Song&);
     void saveRecord(const Song&);
 private:
     std::vector<Song> parseRecords(MYSQL_RES*);