Refactor controllers and update envelope status handling

- Updated `TestEnvelopeHistoryController` to use `EnvelopeStatus` for status parameters and marked it as obsolete.
- Modified `TestViewController` with new route attributes, simplified constructor, and improved error handling in HTTP methods.
- Cleaned up `DebugEnvelopes.cshtml` by removing unnecessary using directives and ensuring type safety in envelope grouping.

EnvelopeGenerator.Web/Views/TestView/DebugEnvelopes.cshtml

@@ -1,5 +1,5 @@
 @using EnvelopeGenerator.CommonServices;
-@using EnvelopeGenerator.Domain;
+@using EnvelopeGenerator.Domain.Entities;
 @using static EnvelopeGenerator.Domain.Constants;
 @{
     ViewData["Title"] = "Debug";
@@ -12,9 +12,9 @@
         return Helpers.EncodeEnvelopeReceiverId(envelope.Uuid, receiver.Signature);
     }
 
-    IEnumerable<IGrouping<EnvelopeStatus, Envelope>> groupEnvelopes(List<Envelope> envelopes) 
+    IEnumerable<IGrouping<EnvelopeStatus, Envelope>> groupEnvelopes(List<Envelope> envelopes)
     {
-        return envelopes.GroupBy(item => item.Status).OrderBy(item => (int)item.Key);
+        return envelopes.GroupBy(item => (EnvelopeStatus) item.Status).OrderBy(item => item.Key);
     }
 }