Introduce support for Jakarta WebSocket 2.1 #29436
Description
Related to #29434, the Jakarta WebSocket API 2.1 introduces a standard mechanism for performing a WebSocket protocol upgrade. While we can use that upgradeHttpToWebSocket method on Tomcat's implementation in TomcatRequestUpgradeStrategy (as per #29434 for compatibility with Tomcat 10.0), we can also introduce a new StandardWebSocketUpgradeStrategy which can use the upgradeHttpToWebSocket method on the Jakarta WebSocket 2.1 ServerContainer interface - and be chosen in AbstractHandshakeHandler when no specific server API has been discovered.