feat(templates): add service language template management

Add normalized service and template catalogs, scoped administration, migration, validation, and regression coverage.

Ref: IT-1601

HrynCo.NotificationService.Web/Views/Shared/_EditorLayout.cshtml

@@ -2,9 +2,10 @@
     Layout = "~/Views/Shared/_Layout.cshtml";
 }
 <div class="editor-wrapper">
+    @RenderSection("Breadcrumbs", required: false)
     <div class="card editor-card">
         <div class="card-header editor-card-header-bar">
-            <i class="bi bi-pencil-square me-2"></i>@ViewData["EditorTitle"]
+            <h1 class="editor-card-title"><i class="bi bi-pencil-square" aria-hidden="true"></i><span>@ViewData["EditorTitle"]</span></h1>
         </div>
         <div class="card-body editor-card-body">
             @RenderBody()