implement message subscribing and worker

dotnet/AipsWorker/Utilities/LoadingDotEnv.cs

@@ -0,0 +1,24 @@
+using DotNetEnv;
+
+namespace AipsWorker.Utilities;
+
+public static class LoadingDotEnv
+{
+    public static bool TryLoad()
+    {
+        string? dir = Directory.GetCurrentDirectory();
+
+        while (dir != null && !File.Exists(Path.Combine(dir, ".env")))
+        {
+            dir = Directory.GetParent(dir)?.FullName;
+        }
+
+        if (dir != null)
+        {
+            Env.Load(Path.Combine(dir, ".env"));
+            return true;
+        }
+
+        return false;
+    }
+}