Replaced Groovy in OCPP module with Java

Replaced Groovy code in OCPP module (ocpp.soap and ocpp.view-model) with Java to get a more consistent use of programming languages across the several Motown modules.

- Replaced Groovy files with Java files in ocpp.soap and ocpp.view-model using IntelliJ's automatic conversion and some additional manual tweaks.
- Removed Groovy compiler from ocpp.soap and ocpp.view-model build configuration.
- Removed Groovy dependencies and properties from root POM.