Combine Log4jWebInitializerImpl into a LoggerContext/LifeCycle wrapper class

This idea is somewhat inspired by Spring's WebApplicationContext/ApplicationContext separation of concerns. Basically, make a WebLoggerContext interface that extends the API LoggerContext interface, have it also extend LifeCycle, and combine the functionality in Log4jWebInitializerImpl into this class instead.

The reasoning for this change is to work on a way to allow the user to perform additional configuration and such in a web container similar to Spring's WebApplicationInitializer interface. This would also provide another stepping stone to programmatic configuration.