feat(frontend): modernize Angular app

ui/src/app/pipes/eta.pipe.ts

@@ -0,0 +1,21 @@
+import { Pipe, PipeTransform } from "@angular/core";
+
+@Pipe({
+    name: 'eta',
+})
+export class EtaPipe implements PipeTransform {
+  transform(value: number): string | null {
+    if (value === null) {
+      return null;
+    }
+    if (value < 60) {
+      return `${Math.round(value)}s`;
+    }
+    if (value < 3600) {
+      return `${Math.floor(value/60)}m ${Math.round(value%60)}s`;
+    }
+    const hours = Math.floor(value/3600)
+    const minutes = value % 3600
+    return `${hours}h ${Math.floor(minutes/60)}m ${Math.round(minutes%60)}s`;
+  }
+}