style: improve design and add logo

- show data icons in thumbnails in data list items
- add app logo
- fix various visibility issues

src/global.scss

@@ -10,3 +10,24 @@
 @import "~@ionic/angular/css/text-transformation.css";
 @import "~@ionic/angular/css/flex-utils.css";
 
+/* StApps */
+
+ion-item {
+  h2.name {
+    font-weight: bold;
+  }
+  ion-thumbnail {
+    background: var(--placeholder-gray);
+    --size: 36px;
+    display: flex;
+    align-items: center;
+    padding: 10px;
+    margin: 0;
+    ion-icon {
+      width: 100%;
+      height: 100%;
+      color: white;
+      display: block;
+    }
+  }
+}