Azure stable loadbalancer outbound IPs

[kon-angelo]

How to categorize this issue?

/area control-plane
/kind enhancement
/platform azure

What would you like to be added:

Configure the azure loadbalancer in such a way that it has stable egress IPs.

Why is this needed:
Currently the outbound IPs for Azure shoots if we are not using NATGateways, depends in the existence of k8s loadbalancer services in the cluster. This creates the following 3 issues:

• It necessitates the creation of allow-egress-tcp/udp services by the extension
• Creates issues with calculation EgressCIDRs since the outbound IPs can change outside the infrastructure step
• We rely in the default outbound access provided by Azure to have the VMs join the cluster and which will be soon deprecated. See Azure info page