Refactor FastCGI server and compiler, enhance HTTP header parsing, and add WebSocket support

- Refactored FastCGIServer class to improve socket handling and added shutdown functionality.
- Updated compiler functions to streamline HTML and text literal processing.
- Enhanced split_kv function to support uppercase keys and added split_http_headers for better HTTP header parsing.
- Introduced new session management functions to validate and handle session IDs.
- Added WebSocket frame parsing and handling in the URI module.
- Created systemd service scripts for easier deployment and management of the UCE FastCGI runtime.
- Added new test cases for header handling, time parsing, and WebSocket functionality.

test/header.uce

@@ -0,0 +1,25 @@
+
+
+RENDER()
+{
+	DTree t;
+
+	<>
+		<link rel="stylesheet" href='style.css'></link>
+		<h1>
+			<a href="index.uce">UCE Test</a>:
+			Header
+		</h1>
+
+		Response Headers
+		<pre style="white-space: pre-wrap"><?
+
+		print(var_dump(context->header));
+
+		?></pre>
+
+		Params
+		<pre><?= var_dump(context->params) ?></pre>
+	</>
+
+}

test/index.uce

@@ -33,6 +33,9 @@ RENDER()
 			<li><a href="task_repeat.uce">Task repeat</a></li>
 			<li><a href="utf8.uce">UTF-8</a></li>
 			<li><a href="call_file.uce">call_file()</a></li>
+			<li><a href="parse_time.uce">parse_time()</a></li>
+			<li><a href="header.uce">header</a></li>
+			<li><a href="websockets.ws.uce">WebSockets</a></li>
 		</ul>
 		<pre><?
 			print("Worker PID: ", my_pid, "\n");

test/parse_time.uce

@@ -0,0 +1,30 @@
+
+RENDER()
+{
+
+	String raw = first(context->post["raw"], "today");
+
+	<>
+		<link rel="stylesheet" href='style.css'></link>
+		<h1>
+			<a href="index.uce">UCE Test</a>:
+			parse_time
+		</h1>
+		<form action="?" method="post">
+			<div>
+				<label>Time string</label>
+				<input type="text" name="raw" value="<?= raw ?>"/>
+			</div>
+			<div>
+				<input type="submit" value="Parse"/>
+			</div>
+		</form>
+		<pre><?
+
+		print(date("%Y-%m-%d %H:%M", parse_time(raw)));
+
+		?></pre>
+		<pre><?= var_dump(context->params) ?></pre>
+	</>
+
+}

test/websockets.ws.uce

@@ -0,0 +1,42 @@
+
+RENDER()
+{
+	String raw = first(context->post["raw"], "today");
+	String server_url = context->params["HTTP_HOST"]+context->params["DOCUMENT_URI"];
+	<>
+		<link rel="stylesheet" href='style.css'></link>
+		<h1>
+			<a href="index.uce">UCE Test</a>:
+			WebSocket Test
+		</h1>
+		<form action="?" method="post">
+			<div>
+				<label></label>
+				<input type="text" name="raw" value="<?= raw ?>"/>
+			</div>
+			<div>
+				<input type="submit" value="Parse"/>
+			</div>
+		</form>
+		<pre id="log"></pre>
+		<script>
+		const ws = new WebSocket('wss://<?= server_url ?>');
+		const log_element = document.getElementById('log');
+		log_element.append('Connecting to wss://<?= server_url ?>...' + "\n");
+		ws.addEventListener('open', (event) => {
+			log_element.append('Connection open' + "\n");
+			ws.send('Hello, server!');
+		});
+		ws.addEventListener('message', (event) => {
+			log_element.append('Message: ' + JSON.stringify(event.data) + "\n");
+		});
+		ws.addEventListener('close', (event) => {
+			log_element.append('Connection closed' + "\n");
+		});
+		ws.addEventListener('error', (event) => {
+			log_element.append('Error: ' + JSON.stringify(event) + "\n");
+		});
+		</script>
+		<pre><?= var_dump(context->params) ?></pre>
+	</>
+}