quic: http/3 getting server settings and customSettings

For applications such as webtransport, http settings are important for negotiating capabilities.

The following problems may be present currently:
1.) I do not see a clear API path for a client that connects to a server to get the settings sent by the server.
Looking at the C++ code, I think the available settings could be on the SessionTicket,
However, if I immediately set a callback to onsessionticket after the Promise for QuicSession is fulfilled, I do not see a call.
@jasnell : Is there another API path to get this information? Or is this a bug, if I do not see the callback? Then I will try to make a test.
2.) nghttp3 does not seem to support settings beyond the settings hardcoded in the library. I will query upstream about implementing a mechanism similar to the customSettings mechanism currently used for http2.

首先跟踪 SessionTicket 和 onsessionticket 周围的 C++ QUIC 实现，然后将 nghttp3 的硬编码设置与 HTTP/2 的 customSettings 机制进行比较。确认服务器设置的预期 API 路径，并为回调传递和自定义设置支持定义测试；当这些行为有明确的实现或上游解决方案时，该 issue 即完成。