Only send requested-family for ipv6 allocations

Fixed channel number reuse, added server logs (#541)

Do not delete the client-side binding when a ChannelBind transaction
fails. This keeps the channel number stable for a peer even if
a response is lost, preventing "same peer, different channel" rebind
attempts.

Server already has channel-bind conflict detection implemented
and handled it silently. Added server warning logs in ChannelBind
handling to help discover and debug similar issues in the future.

Relase v5.0.0

Upgrade to pion/transport/v4

Handle stale nonces in ChannelBind

And add timer to renew bindings

Wrapped TURN errors (#480)

* Wrapped TURN Allocation/Permission errors

Fix lint issues with golangci-lint@v2

Add a quota handler callback

This PR adds a quota handler callback function which, if specified, is
called by the server just before making an allocation for a user. The
handler should return a single bool: if true then the allocation
request can proceed, otherwise the request is rejected with a 486
(Allocation Quota Reached) error.

Lower priority of per-packet error message

The error message "Failed to handle datagram" is generated for
each received packet; it can therefore be used by an attacker to
fill the server's logs by sending a burst of incorrect packets.

Lower its priority to debug.

Avoid calling String() on nil turn address