Fixes: RIPD-1574
Alias beast address classes to the asio equivalents. Adjust users of
address classes accordingly. Fix resolver class so that it can support
ipv6 addresses. Make unit tests use ipv6 localhost network. Extend
endpoint peer message to support string endpoint
representations while also supporting the existing fields (both are
optional/repeated types). Expand test for Livecache and Endpoint.
Workaround some false positive ipaddr tests on windows (asio bug?)
Replaced usage of address::from_string(deprecated) with free function
make_address. Identified a remaining use of v4 address type and
replaced with the more appropriate IPEndpoint type (rpc_ip cmdline
option). Add CLI flag for using ipv4 with unit tests.
Release Notes
-------------
The optional rpc_port command line flag is deprecated. The rpc_ip
parameter now works as documented and accepts ip and port combined.
In support of dynamic validator list, this changeset:
1. Adds a new `validator_list_expires` field to `server_info` that
indicates when the current validator list will become stale.
2. Adds a new admin only `validator_lists` RPC that returns the
current list of known validators and the most recent published validator
lists.
3. Adds a new admin only `validator_sites` RPC that returns the list of
configured validator publisher sites and when they were most recently
queried.
