This commit improves support for use of Spring Session with Hazelcast's client-server topology by ensuring SessionUpdateEntryProcessor is easier to serialize to the cluster. This is done by refactoring SessionUpdateEntryProcessor from static inner class of HazelcastSessionRepository to a dedicated class, therefore minimizing the dependencies to other Spring Session components.
Closes gh-1101
This commit improves dependency management with the following changes:
- `spring-session-core`: move `javax.servlet-api` from `provided` to `optional` configuration due to introduction of reactive support
- `spring-session-data-redis`: remove Redis driver from `compile` configuration
- Boot samples: delegate Redis driver choice to `spring-boot-starter-data-redis`
- polish `test` configuration dependencies
