UX - focus username field on page load (#904)

<img width="795" alt="Screenshot 2024-10-22 at 15 41 54"
src="https://github.com/user-attachments/assets/7ca6d337-82e2-4666-83a7-ef7c691b1d53">

Author: nablaone

quesma/quesma/ui/login.go

@@ -22,7 +22,7 @@ func (qmc *QuesmaManagementConsole) generateLoginForm() []byte {
 	buffer.Html(`<p style="color: #ccc;">Log in to Quesma admin console using your Elasticsearch credentials</p>`)
 	buffer.Html(`<form action="/login-with-elasticsearch" method="post">`)
 	buffer.Html(`<label for="username">Username:</label>`)
-	buffer.Html(`<input type="text" id="username" name="username" placeholder="Enter your Elasticsearch username">`)
+	buffer.Html(`<input type="text" id="username" name="username" placeholder="Enter your Elasticsearch username" autofocus>`)
 	buffer.Html(`<label for="password">Password:</label>`)
 	buffer.Html(`<input type="password" id="password" name="password" placeholder="Enter your Elasticsearch password">`)
 	buffer.Html(`<input type="submit" value="Login">`)