This replaces the current epee logging system with our oxen::log
library. It replaces the easylogging library with spdlog, removes the
macros and replaces with functions and standardises how we call the
logs.
Converts all use of boost::filesystem to std::filesystem.
For macos and potentially other exotic systems where std::filesystem
isn't available, we use ghc::filesystem instead (which is a drop-in
replacement for std::filesystem, unlike boost::filesystem).
This also greatly changes how we handle filenames internally by holding
them in filesystem::path objects as soon as possible (using
fs::u8path()), rather than strings, which avoids a ton of issues around
unicode filenames. As a result this lets us drop the boost::locale
dependency on Windows along with a bunch of messy Windows ifdef code,
and avoids the need for doing gross boost locale codecvt calls.
07b9138c support importing unportable outputs (kenshi84)
2ac80075 also use portable serializer for boost_serialization_helper.h and net_node.inl, completely adandon boost/archive/binary_oarchive.hpp (kenshi84)
d1d6e27a moved boost cpp into hpp since they're supposed to be header only (kenshi84)
66e6af89 added experimental boost::archive::portable_binary_{i|o}archive (kenshi84)