MINOR: server/bind: add support of new prefixes for addresses.

MINOR: server/bind: add support of new prefixes for addresses.

Since the internal function str2sa_range is used to addresses
for different objects ('server', 'bind' but also 'log' or
'nameserver') we notice that some combinations are missing.

"ip@" is introduced to authorize the prefix "dgram+ip@" or
"stream+ip@" which dectects automatically IP version but
specify dgram or stream.

"tcp@" was introduced and is an alias for "stream+ip@".
"tcp6" and "tcp4" are now aliases for "stream+ipv6@" and
"stream+ipv4@".

"uxst@" and "uxdg@" are now aliases for "stream+unix@" and
"dgram+unix@".

This patch also adds a complete section in documentation to
describe adresses and their prefixes.