vine: manager contact address

[btovar]

In settings such as coffea-casa the addresses that the manager detects for itself are unrelated to the address that workers should use to contact it. The correct contact host and port can be read somewhere from the environment. The manager needs an initialization argument like contact_hostport=... to report this address to the catalog. If the contact address is not an ip, then the manager should switch to by_hostname connection mode.