treewide: Update JS using luci-rpc getHostHints

Update frontend JS code which uses luci-rpc getHostHints to support the new
response format which removes the `ipv4` and `ipv6` host hint string fields
and replaces them with `ipaddrs` and `ip6addrs` weighted string list fields.

Signed-off-by: Niels Widger <niels@qacafe.com>
[rework code to be forwards/backwards compatible, fix some Network.Hosts
 methods, fix IP choice ordering, change commit subject, rewrap commit
 message]
Signed-off-by: Jo-Philipp Wich <jo@mein.io>