Remove password, used to access Restconf.

Use environment variables pattern, provided by configuration class to access environment variable:  e.g. "${SDNRDBURL}" (See /sdnr-wt-data-provider-provider/src/main/java/org/onap/ccsdk/features/sdnr/wt/dataprovider/impl/EsConfig.java).

Variables are provided via OOM setup script.