Remove Narayana support

The Spring Boot integration is now handled by the Narayana project
itself at https://github.com/snowdrop/narayana-spring-boot

This commit removes our support.

Closes gh-12026

spring-boot-project/spring-boot-starters/pom.xml

@@ -50,7 +50,6 @@
 		<module>spring-boot-starter-json</module>
 		<module>spring-boot-starter-jta-atomikos</module>
 		<module>spring-boot-starter-jta-bitronix</module>
-		<module>spring-boot-starter-jta-narayana</module>
 		<module>spring-boot-starter-logging</module>
 		<module>spring-boot-starter-log4j2</module>
 		<module>spring-boot-starter-mail</module>