Upgrade to Spring Boot 3.2

[arolfes]

Upgrade to SpringBoot 3.2

https://github.com/spring-projects/spring-boot/wiki/Spring-Boot-3.2-Release-Notes

Refactore RestTemplate to use new RestClient

https://docs.spring.io/spring-boot/docs/3.2.0-SNAPSHOT/reference/html//io.html#io.rest-client.restclient