Add `VmessIntoOutboundDetour` for v2ray json config file generation

[yindaheng98]

The code in the function Vmess2Outbound that turn a VmessLink into OutboundDetourConfig is great! Want reuse this code when develop some tools that use vmessping to test v2ray nodes and generate config.json: vmessconfig and yindaheng98/v2confserver, I made this pull request.