Warn if HERMIT_IP is set and dhcpv4 feature is enabled

[jounathaen]

As dhcpv4 is a default feature, it is easy to forget that it is set. If one sets HERMIT_IP (orHERMIT_GATEWAY/HERMIT_MASK) with dhcpv4 enabled, the value from the environment is ignored.

I suggest emitting a warning if dhcpv4 is enabled and HERMIT_IP, HERMIT_GATEWAY, or HERMIT_MASK is set.

(Probably just needs a few lines in

kernel/src/executor/device.rs

Line 43 in 285f28a

pub(crate) fn create() -> NetworkState<'a> {

)