Refactoring diagnostic tests in multiple files.

server/lib/diagnostic/backend.ts

@@ -0,0 +1,9 @@
+import { newResult, TestResult } from './utils'
+
+export async function diagBackend (test: string, _settingsManager: PluginSettingsManager): Promise<TestResult> {
+  const result = newResult(test)
+  result.label = 'Backend connection'
+  result.ok = true
+  result.next = 'webchat-video'
+  return result
+}