net/turnserver: need external-ip in turnserver.conf

[bonjour-py]

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Is your feature request related to a problem? Please describe.

my opensense behind a 1:1NAT, turnserver can not set correct ip for clients.

Describe the solution you'd like

need set external-ip in turnserver.conf.

Describe alternatives you've considered I have no idea

Additional context

https://github.com/coturn/coturn/blob/24e99eca1cf84ad83f050c957e745ed12edcfeff/docker/coturn/turnserver.conf#L108

# For Amazon EC2 users:
#
# TURN Server public/private address mapping, if the server is behind NAT.
# In that situation, if a -X is used in form "-X <ip>" then that ip will be reported
# as relay IP address of all allocations. This scenario works only in a simple case
# when one single relay address is be used, and no RFC5780 functionality is required.
# That single relay address must be mapped by NAT to the 'external' IP.
# The "external-ip" value, if not empty, is returned in XOR-RELAYED-ADDRESS field.
# For that 'external' IP, NAT must forward ports directly (relayed port 12345
# must be always mapped to the same 'external' port 12345).
#
# In more complex case when more than one IP address is involved,
# that option must be used several times, each entry must
# have form "-X <public-ip/private-ip>", to map all involved addresses.
# RFC5780 NAT discovery STUN functionality will work correctly,
# if the addresses are mapped properly, even when the TURN server itself
# is behind A NAT.
#
# By default, this value is empty, and no address mapping is used.
#
#external-ip=60.70.80.91
#
#OR:
#
#external-ip=60.70.80.91/172.17.19.101
#external-ip=60.70.80.92/172.17.19.102