[Documentation]: Document how to publish MetalLB Service IP on the Internet

[outscale-hmi]

What happened

We have a use case to use the Cluster API Outscale Provider in conjunction with MetalLB to assign IP addresses to Kubernetes Services. These IP addresses are automatically allocated from a configured IP pool within MetalLB. However, we need to publish these assigned IPs on the internet to enable external access to the services.

The IPs are not tied to specific VMs but are instead managed directly by MetalLB. We need guidance on how to route traffic from the internet to these IP addresses while leveraging the Cluster API Outscale Provider.

Context:
We are deploying Kubernetes clusters using the Cluster API Outscale Provider.
MetalLB is configured to provide external IPs from a predefined pool.

Step to reproduce

none

Expected to happen

We want to publish the IPs assigned by MetalLB so they are accessible from the internet.

Add anything

none

cluster-api output

none

Environment

- Kubernetes version: (use `kubectl version`): 
- OS (e.g. from `/etc/os-release`):
- Kernel (e.g. `uname -a`):
- cluster-api-provider-outscale version:
- cluster-api version: 
- Install tools:
- Kubernetes Distribution:
- Kubernetes Diestribution version:

[outscale-hmi]

#391