XD-1126 switch CAPITAL_LETTERS to system.property conventions

This one required a lot of manual testing with various command line options, environment variables and server.yml settings against singlenode, admin, and container. 

A couple of command line options have to stay in upper case AFAICT, e.g.,  XD_CONTAINER_GROUPS, XD_MGMT_PORT (names with more than two parts which don't map correctly using the prefix attribute,  @ConfigurationProperties(prefix="xd")).  

Added --verbose to dump all property values

Got rid of XdPropertyKeys