Consider transport concerns re Spring Tomcat

[officialyinsane]

A discussion happened in Discord, where it was stated that we're currently using Tomcat, but Netty supports non-blocking IO better. Equally, Undertow might be warranted for performance, or Jetty).

See https://docs.spring.io/spring-boot/docs/2.1.9.RELEASE/reference/html/howto-embedded-web-servers.html for some context.

Raised as a discussion point, more than a requirement.