Adding nix shell and reworking some parser/local file manager stuff

SzLib/Class1.cs

@@ -1,6 +0,0 @@
-namespace SzLib;
-
-public class Class1
-{
-
-}

SzLib/ISzFileManager.cs

@@ -1,8 +1,12 @@
+using SzLib.DataObjects;
+
 namespace SzLib;
 
 public interface ISzFileManager 
-{
+{ 
     public string DataPath {get;}
-
+    public string DatasetsPath {get;}
+    
     public bool SaveFile(string path, string fileContent);
-}
+    public string? LoadFile(string path);
+}

SzLib/SzParser.cs

@@ -35,13 +35,12 @@ public class SzParser(ISzFileManager szFileManager)
 
     public bool SaveDataset(SzDataset dataset)
     {
-        var datasetDir = Path.Combine(szFileManager.DataPath, "datasets", dataset.Id);
-        Directory.CreateDirectory(datasetDir);
+        var datasetDir = Path.Combine(szFileManager.DatasetsPath, dataset.Id);
+
         try
         {
             var json = SerializeDatasetToJson(dataset);
-            File.WriteAllText(Path.Combine(datasetDir, "dataset.json"), json);
-            return true;
+            return szFileManager.SaveFile(Path.Combine(datasetDir, "dataset.json"), json);
         }
         catch (Exception e)
         {