peermap/ui: remove documentation link from sign-in page

disco/udp: make relayprotocol works better

disco/udp: ignore packets from ip in the ignore list

oci_image: peerguard -> openpg

peermap: add ui(#26)

disco: add nat type `easy+ip6`

disco/udp: add cache for func UDPConn.findPeerID

pgcli/vpn: add user/pass auth for proxy server(#28)

disco/ws: handle http 404 error

helps with issues of type #25

disco/udp: graceful close