The MultiSocket is obsolete technology which is superceded by a more
straightforward, template based implementation that is compatible with
boost::asio::coroutines. This removes support for the unused PROXY handshake
feature. After this change a large number of classes and source files may be
removed.
* Remove all calls to setlocale to ensure that the global
locale is always C.
* Also replace beast::SystemStats::getNumCpus() with
std:🧵:hardware_concurrency()
* More fine-grained Section mutators
* Add remap for mapping legacy single sections to key value pairs
* Add output stream operators for BasicConfig and Section
* Allow section values to be overwritten from command line
* Update rpc key/value configs from command line
* Add RPC::Setup with defaults and remap legacy rpc sections