some updates for pom (#1879)

* move version to parent pom

* move version properties to parent pom for easy management

* remove freemarker dependency

* delete CombinedApplicationServer

* #1871 correct spelling

* #1873 some updates for TaskQueueZkImpl

* #1875 remove unused properties in pom

* #1878
1. remove tomcat dependency
2. remove combined_logback.xml in api module
3. format pom.xml for not aligning