Implement the Jakarta Servlet 6.1 specification for the Undertow Servlet implementation. The required changes can be seen in the specification document.

Some specific issues to verify:

• https://github.com/jakartaee/servlet/issues/164
• https://github.com/jakartaee/servlet/issues/273
• https://github.com/jakartaee/servlet/issues/275
• https://github.com/jakartaee/servlet/issues/300
• https://github.com/jakartaee/servlet/issues/316 - Likely related to https://github.com/jakartaee/servlet/issues/300
• https://github.com/jakartaee/servlet/issues/325
• https://github.com/jakartaee/servlet/issues/431
• https://github.com/jakartaee/servlet/issues/453
• https://github.com/jakartaee/servlet/issues/468
• https://github.com/jakartaee/servlet/issues/469
• https://github.com/jakartaee/servlet/issues/484
• https://github.com/jakartaee/servlet/issues/538
• https://github.com/jakartaee/servlet/issues/546