Add support for Filter-type function

[olegz]

Currently we have RoutingFunction

It would be nice to have a filtering function especially when encountering cases like this

[emckissick]

Hello, Would this feature allow a user to create a Function that passes the Message to the next function only if it meets a specific criteria? (https://stackoverflow.com/questions/77801389/skip-filtering-in-spring-cloud-stream-workflow/77802387#77802387).