net.mbedtls: add SSLListener to allow creating SSL servers (#19022)

examples/ssl_server/server.v

@@ -0,0 +1,20 @@
+import io
+import os
+import net.mbedtls
+
+fn main() {
+	mut server := mbedtls.new_ssl_listener('0.0.0.0:8443', mbedtls.SSLConnectConfig{
+		verify: os.resource_abs_path('cert/ca.crt')
+		cert: os.resource_abs_path('cert/server.crt')
+		cert_key: os.resource_abs_path('cert/server.key')
+		validate: true // mTLS
+	})!
+
+	mut client := server.accept()!
+	mut reader := io.new_buffered_reader(reader: client)
+	mut request := reader.read_line()!
+	println(request)
+	client.write_string('HTTP/1.1 200 OK\r\n')!
+	client.shutdown()!
+	server.shutdown()!
+}