feat(engine): retrieve bpm-platform.xml location from various sources

- fix testcases for windows

related to CAM-1240
fix(tomcat-qa): disable resource locking for tomcat
feat(engine): retrieve bpm-platform.xml location from various sources

- add null checks

related to CAM-1240
fix(engine-rest): provide correct maven settings.xml
feat(engine): retrieve bpm-platform.xml location from various sources

- allow to retrieve bpm-platform.xml from environment variable

related to CAM-1240