refactor: rename Api project to Web

- HrynCo.NotificationService.Api -> HrynCo.NotificationService.Web
- HrynCo.NotificationService.Api.IntegrationTests -> HrynCo.NotificationService.Web.IntegrationTests
- Updated slnx, docker-compose, project references, and namespaces
- Project serves both REST API and admin UI

Ref: IT-628

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

HrynCo.NotificationService.Web/appsettings.Development.json

@@ -0,0 +1,12 @@
+{
+  "Serilog": {
+    "MinimumLevel": {
+      "Default": "Debug",
+      "Override": {
+        "Microsoft": "Information",
+        "Microsoft.EntityFrameworkCore": "Information",
+        "Microsoft.AspNetCore": "Information"
+      }
+    }
+  }
+}