Merge ejb3 ScheduleTimer and AutoTimer classes

The 2 classes are mostly overlapping and should be combined into one: keep AutoTimer and remove ScheduleTimer. There will need some refactoring in various places as a result of the merger.

https://github.com/wildfly/wildfly/blob/main/ejb3/src/main/java/org/jboss/as/ejb3/timerservice/AutoTimer.java

https://github.com/wildfly/wildfly/blob/main/ejb3/src/main/java/org/jboss/as/ejb3/timerservice/spi/ScheduleTimer.java