chore: scaffold solution with Core, Api, Worker and test projects

- HrynCo.NotificationService.Core (class library)
- HrynCo.NotificationService.Api (ASP.NET Core Web API)
- HrynCo.NotificationService.Worker (Worker Service)
- HrynCo.NotificationService.Core.Tests (xUnit)
- HrynCo.NotificationService.Api.IntegrationTests (xUnit)
- Api and Worker reference Core
- Test projects reference their respective targets

Ref: IT-628

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

HrynCo.NotificationService.Api/Properties/launchSettings.json

@@ -0,0 +1,23 @@
+{
+  "$schema": "https://json.schemastore.org/launchsettings.json",
+  "profiles": {
+    "http": {
+      "commandName": "Project",
+      "dotnetRunMessages": true,
+      "launchBrowser": false,
+      "applicationUrl": "http://localhost:5188",
+      "environmentVariables": {
+        "ASPNETCORE_ENVIRONMENT": "Development"
+      }
+    },
+    "https": {
+      "commandName": "Project",
+      "dotnetRunMessages": true,
+      "launchBrowser": false,
+      "applicationUrl": "https://localhost:7210;http://localhost:5188",
+      "environmentVariables": {
+        "ASPNETCORE_ENVIRONMENT": "Development"
+      }
+    }
+  }
+}