docs: group Angular pages based on topic

docs/en/docs-nav.json

@@ -436,76 +436,96 @@
               "path": "UI/Angular/Quick-Start.md"
             },
             {
-              "text": "Environment",
-              "path": "UI/Angular/Environment.md"
-            },
-            {
-              "text": "Service Proxies",
-              "path": "UI/Angular/Service-Proxies.md"
-            },
-            {
-              "text": "HTTP Requests",
-              "path": "UI/Angular/HTTP-Requests.md"
-            },
-            {
-              "text": "Localization",
-              "path": "UI/Angular/Localization.md"
-            },
-            {
-              "text": "Permission Management",
-              "path": "UI/Angular/Permission-Management.md"
-            },
-            {
-              "text": "Multi Tenancy",
-              "path": "UI/Angular/Multi-Tenancy.md"
-            },
-            {
-              "text": "Confirmation Popup",
-              "path": "UI/Angular/Confirmation-Service.md"
-            },
-            {
-              "text": "Toast Overlay",
-              "path": "UI/Angular/Toaster-Service.md"
-            },
-            {
-              "text": "Config State",
-              "path": "UI/Angular/Config-State.md"
-            },
-            {
-              "text": "Modifying the Menu",
-              "path": "UI/Angular/Modifying-the-Menu.md"
-            },
-            {
-              "text": "Component Replacement",
-              "path": "UI/Angular/Component-Replacement.md"
-            },
-            {
-              "text": "Custom Setting Page",
-              "path": "UI/Angular/Custom-Setting-Page.md"
-            },
-            {
-              "text": "Lazy Loading Scripts & Styles",
-              "path": "UI/Angular/Lazy-Load-Service.md"
-            },
-            {
-              "text": "DomInsertionService",
-              "path": "UI/Angular/Dom-Insertion-Service.md"
-            },
-            {
-              "text": "ContentProjectionService",
-              "path": "UI/Angular/Content-Projection-Service.md"
+              "text": "Development",
+              "items": [
+                {
+                  "text": "Environment Variables",
+                  "path": "UI/Angular/Environment.md"
+                },
+                {
+                  "text": "Service Proxies",
+                  "path": "UI/Angular/Service-Proxies.md"
+                }
+              ]
             },
             {
-              "text": "TrackByService",
-              "path": "UI/Angular/Track-By-Service.md"
+              "text": "Core Functionality",
+              "items": [
+                {
+                  "text": "Config State",
+                  "path": "UI/Angular/Config-State.md"
+                },
+                {
+                  "text": "HTTP Requests",
+                  "path": "UI/Angular/HTTP-Requests.md"
+                },
+                {
+                  "text": "Localization",
+                  "path": "UI/Angular/Localization.md"
+                },
+                {
+                  "text": "Permission Management",
+                  "path": "UI/Angular/Permission-Management.md"
+                },
+                {
+                  "text": "Multi Tenancy",
+                  "path": "UI/Angular/Multi-Tenancy.md"
+                }
+              ]
             },
             {
-              "text": "SubscriptionService",
-              "path": "UI/Angular/Subscription-Service.md"
+              "text": "Utilities",
+              "items": [
+                {
+                  "text": "RxJS Subscriptions",
+                  "path": "UI/Angular/Subscription-Service.md"
+                },
+                {
+                  "text": "Working with Lists",
+                  "path": "UI/Angular/List-Service.md"
+                },
+                {
+                  "text": "Easy *ngFor trackBy",
+                  "path": "UI/Angular/Track-By-Service.md"
+                },
+                {
+                  "text": "Inserting Scripts & Styles to DOM",
+                  "path": "UI/Angular/Dom-Insertion-Service.md"
+                },
+                {
+                  "text": "Lazy Loading Scripts & Styles",
+                  "path": "UI/Angular/Lazy-Load-Service.md"
+                },
+                {
+                  "text": "Projecting Angular Content",
+                  "path": "UI/Angular/Content-Projection-Service.md"
+                },
+                {
+                  "text": "Confirmation Popup",
+                  "path": "UI/Angular/Confirmation-Service.md"
+                },
+                {
+                  "text": "Toast Overlay",
+                  "path": "UI/Angular/Toaster-Service.md"
+                }
+              ]
             },
             {
-              "text": "ListService",
-              "path": "UI/Angular/List-Service.md"
+              "text": "Customization",
+              "items": [
+                {
+                  "text": "Modifying the Menu",
+                  "path": "UI/Angular/Modifying-the-Menu.md"
+                },
+                {
+                  "text": "Component Replacement",
+                  "path": "UI/Angular/Component-Replacement.md"
+                },
+                {
+                  "text": "Custom Setting Page",
+                  "path": "UI/Angular/Custom-Setting-Page.md"
+                }
+              ]
             }
           ]
         },