This commit add a Cilium config struct parsed from the etcd config to connect
to each remote clustermesh-apiserver. These fields are ignored by etcd
which ignore any unknown fields (like most go program do) and will be
used in a future commit to replace the host aliases on Pods which forces
restarts when changed.

Signed-off-by: Arthur Outhenin-Chalandre <git@mrfreezeex.fr>

Add a new static dialier and wire it in the clustermesh code with the
config that was added in the previous commit.

This new static dialer attempt to be very close to the net.Dialer with very
similar code and partially the same behavior (it has to be a bit
different since we don't resolve anything though). It only match one single
hostname and will fallback to another dialer so that we can just chain
dialer like the one we are already using.

This dialer will attempt every IPs and if the context has a deadline
set it will have partial distribution logic which essentially boils down to
dividing the remaining deadline from the original context with the number of
remaining IPs to attempt connection to. This logic is directly taken from the
net.Dialer logic. Note that to my knowledge we don't have any deadline set
in the ClusterMesh code though.

Signed-off-by: Arthur Outhenin-Chalandre <git@mrfreezeex.fr>

Add the cilium-host-aliases in the etcd config which should be fully replacing
hostaliases in Cilium 1.21. We are keeping hostAliases for now to keep
downgrade safe (secrets updated without cilium-clustermesh-apiserver-host and
potentially without hostAliases if we were already removing it here).

We are force disabling this in the conformance ClusterMesh CI via a non
documented helm values to already exercise that this is working properly
while the conformance upgrade CI stays on default setting to keep the
existing flow tested!

Signed-off-by: Arthur Outhenin-Chalandre <git@mrfreezeex.fr>