Consider improving configuration support for ConfigureRedisAction

[vpavic]

Since configuring ConfigureRedisAction#NO_OP is quite essential for production environments, we could consider enhancing our Redis configuration support. For example, we could consider exposing it over @EnableRedisHttpSession in some way.

Note that Spring Boot has recently added support for this in spring-projects/spring-boot#17022.

[vpavic]

I don't feel like this is needed, as registering bean aligns nicely with other customizations we allow in @Enable...Session based configurations, while Spring Boot auto-configuration support offers further convenience using its configuration properties.

WDYT @rwinch?