✨ edge subnets/docs: added guide subnets on Local and Wavelength zones

Create a dedicated document, "topic", with instructions to deploy
network infrastructure (subnets, gateways and route tables) in "edge
zones" - Local Zone and Wavelength Zone infrastructure.

Author: mtulio

docs/book/src/topics/provision-edge-zones.md

@@ -2,14 +2,19 @@
 
 ## Overview
 
-CAPA provides the option to manage network resources on AWS Local Zone locations.
+CAPA provides the option to manage network resources required to provision compute nodes
+to Local Zone and Wavelength Zone locations.
 
 [AWS Local Zones](https://aws.amazon.com/about-aws/global-infrastructure/localzones/)
 extends the cloud infrastructure to metropolitan regions,
 allowing to deliver applications closer to the end-users, decreasing the
 network latency.
 
-When "edge zones" is mentioned in this document, it is referencing AWS Local Zones.
+[AWS Wavelength Zones](https://aws.amazon.com/wavelength/)
+extends the AWS infrastructure deployments infrastructure to carrier infrastructure,
+allowing to deploy within communications service providers’ (CSP) 5G networks.
+
+When "edge zones" is mentioned in this document, it is referencing to AWS Local Zones and AWS Wavelength Zones.
 
 ## Requirements and defaults
 
@@ -19,7 +24,8 @@ For both Local Zones and Wavelength Zones ('edge zones'):
 - When you choose to CAPA manage edge zone's subnets, you also must specify the
   regular zones (Availability Zones) you will create the cluster.
 - IPv6 is not globally supported by AWS across Local Zones,
-  CAPA support is limited to IPv4 subnets in edge zones.
+  and is not supported in Wavelength zones, CAPA support is limited to IPv4
+  subnets in edge zones.
 - The subnets in edge zones will not be used by CAPA to create NAT Gateways,
   Network Load Balancers, or provision Control Plane or Compute nodes by default.
 - NAT Gateways are not globally available to edge zone's locations, the CAPA uses
@@ -31,6 +37,8 @@ For both Local Zones and Wavelength Zones ('edge zones'):
   can be used to create a load balancer for API.
 - It is required to manually opt-in to each zone group for edge zones you are planning to create subnets.
 
+The following steps are example to describe the zones and opt-into an zone group for an Local Zone:
+
     - To check the zone group name for a Local Zone, you can use the [EC2 API `DescribeAvailabilityZones`][describe-availability-zones]. For example:
 ```sh
 aws --region "<value_of_AWS_Region>" ec2 describe-availability-zones \
@@ -98,4 +106,69 @@ spec:
       isPublic: true
 ```
 
+## Installing managed clusters extending subnets to Wavelength Zones
+
+To create a cluster with support of subnets on AWS Wavelength Zones, add the `Subnets` stanza to your `AWSCluster.NetworkSpec`. Example:
+
+```yaml
+---
+apiVersion: infrastructure.cluster.x-k8s.io/v1beta2
+kind: AWSCluster
+metadata:
+  name: aws-cluster-wavelengthzone
+spec:
+  region: us-east-1
+  networkSpec:
+    vpc:
+      cidrBlock: "10.0.0.0/20"
+    subnets:
+    # <placeholder for regular zones (availability zones)>
+    - availabilityZone: us-east-1-wl1-was-wlz-1
+      cidrBlock: "10.0.128.0/25"
+      id: "cluster-subnet-private-us-east-1-wl1-was-wlz-1"
+      isPublic: false
+    - availabilityZone: us-east-1-wl1-was-wlz-1
+      cidrBlock: "10.0.128.128/25"
+      id: "cluster-subnet-public-us-east-1-wl1-was-wlz-1"
+      isPublic: true
+```
+
+## Installing managed clusters extending subnets to Local and Wavelength Zones
+
+It is also possible to mix the creation across both Local and Wavelength zones.
+
+To create a cluster with support of edge zones, add the `Subnets` stanza to your `AWSCluster.NetworkSpec`. Example:
+
+```yaml
+---
+apiVersion: infrastructure.cluster.x-k8s.io/v1beta2
+kind: AWSCluster
+metadata:
+  name: aws-cluster-edge
+spec:
+  region: us-east-1
+  networkSpec:
+    vpc:
+      cidrBlock: "10.0.0.0/20"
+    subnets:
+    # <placeholder for regular zones (availability zones)>
+    - availabilityZone: us-east-1-nyc-1a
+      cidrBlock: "10.0.128.0/25"
+      id: "cluster-subnet-private-us-east-1-nyc-1a"
+      isPublic: false
+    - availabilityZone: us-east-1-nyc-1a
+      cidrBlock: "10.0.128.128/25"
+      id: "cluster-subnet-public-us-east-1-nyc-1a"
+      isPublic: true
+    - availabilityZone: us-east-1-wl1-was-wlz-1
+      cidrBlock: "10.0.129.0/25"
+      id: "cluster-subnet-private-us-east-1-wl1-was-wlz-1"
+      isPublic: false
+    - availabilityZone: us-east-1-wl1-was-wlz-1
+      cidrBlock: "10.0.129.128/25"
+      id: "cluster-subnet-public-us-east-1-wl1-was-wlz-1"
+      isPublic: true
+```
+
+
 [describe-availability-zones]: https://docs.aws.amazon.com/AWSEC2/latest/APIReference/API_DescribeAvailabilityZones.html