when loading service.properties, allow to use ${variable} notation everywhere

...er/source/java/ch/systemsx/cisd/etlserver/Parameters.java

...emsx/cisd/openbis/dss/generic/server/DataStoreServer.java

...neric/server/plugins/tasks/AbstractPluginTaskFactory.java

...nbis/dss/generic/shared/utils/PropertyParametersUtil.java