[fix] #170: endpoint: Fix ipv4/host attributes mix up

In case only an IPv4 is present, the latter ends up in server/host attribute
Since HOST_REGEX is using dots, the IPv4 is matched as a host

Only happening to BMA(S) and GVA since the other endpoints' regex are
matiching one among (host|ipv6|ipv4)

Use ipaddress as a trick after regex matching to
switch ipv4 and server/host attributes