prefer more flexible get_local_ip where possible

prefer more flexible get_local_ip where possible

get_ip_from_hostname does only check getaddrinfo, which can fail for
the local node in some environments, especially container ones.

Rather, use the new get_local_ip helper, that still tries to do a gai
call first, but falls back to configured (/etc/network/interfaces)
IPs and also on the currently, from kernel POV active ones.

A big bonus is that the new helper is much less likely to die, so it
won't break service startup in restricted (CTs) envs after initial
setup as often anymore.

While yes, if no addr is resolved, configured or active the PMG won't
work, but killing pmg proxy/daemon won't better that situation either
;)

Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>