implement delete_connection Admin API call

References: https://todo.sr.ht/~eduvpn/server/178
add /connection_list Admin API call
move generate-prefix script to libexec
add script to generate random IPv4 and IPv6 prefixes
prepare for release
update CHANGES
wrap /v1/connected_users Admin API response in object
update CHANGES
Revert "expose `TCPEndpoint` option as a comment in WireGuard config"

This reverts commit d24d9696ae57a0ae65d8562f8175d333da33d71c.
update CHANGES
fix user sessionExpiry override

we forgot to consider the attribute name in front of the attribute value
Fixes: https://todo.sr.ht/~eduvpn/server/175
expose `TCPEndpoint` option as a comment in WireGuard config

in case a TCP proxy is available on the VPN server for WireGuard
connections it is advertised in the configuration file as
`#TCPEndpoint`. The endpoint can be used with ProxyGuard
return error if user not exists when using Admin API
add missing bracket
implement /v1/users and /v1/disabled_users Admin API calls

Fixes: https://todo.sr.ht/~eduvpn/server/171