Add allocation-pool support for the public_net

TripleO CI uses 10.0.0.1 statically for the undercloud's
public interface. When using extra node in some job's
there is sometime a conflict, because the extra node get's
the 10.0.0.1 address allocated.

Adding support to define the allocation pools on the
public_net allows TripleO CI to define a pool with the
10.0.0.1 address eliminated.

A good practice would be to set up OVB to use
[{start: 10.0.0.128, end: 10.0.0.253}], and then configure
the undercloud/overcloud deployed on the OVB infrastructure
to use addresses in the range 10.0.0.1-10.0.0.127.

The parameter public_net_allocation_pools controls the
allocation pool setting, by default all addresses of the
subnet is in the pool.

Related-Bug: #1874418
Change-Id: Ieca4864e069148abb49eb709bf7f48a14ef04e77
(cherry picked from commit ccec11f9c8)

Fix type of public_net_allocation_pools

https://review.opendev.org/#/c/733598/ added support
of allocation_pools, but set type of public_net_allocation_pools
to comma_delimited_list which causes below issue because for
comma_delimited_list, list items are converted to string:-

Property error: : resources.public_subnet.properties.allocation_pools[0]:
"{'end': '10.0.0.199', 'start': '10.0.0.128'}" is not a map

We need to use type: json to get it work, this patch fixes it.

Related-Bug: #1874418
Change-Id: Iaebb297e5018ce8db6dd1f67a308e7707117fe03
(cherry picked from commit ff4d8fa4e2)

environments/base.yaml

@@ -61,6 +61,18 @@ parameter_defaults:
   # Type: string
   public_net: public
 
+  # Allocation Pools for the public network
+  # Type: json
+  public_net_allocation_pools: []
+
+  # CIDR for external network subnet
+  # Type: string
+  public_net_cidr: 10.0.0.0/24
+
+  # IP version for the public subnet
+  # Type: number
+  public_net_ip_version: 4
+
   # Whether this network should be shared across all tenants
   # Type: boolean
   public_net_shared: False

sample-env-generator/environments.yaml

@@ -15,6 +15,9 @@ environments:
           - baremetal_prefix
           - node_count
           - public_net
+          - public_net_cidr
+          - public_net_allocation_pools
+          - public_net_ip_version
           - public_net_shared
           - provision_net
           - provision_net_shared

templates/quintupleo.yaml

@@ -69,6 +69,11 @@ parameters:
     description: Name of the overcloud external network
     default: public
 
+  public_net_allocation_pools:
+    type: json
+    description: Allocation Pools for the public network
+    default: []
+
   public_net_cidr:
     type: string
     description: CIDR for external network subnet
@@ -200,6 +205,7 @@ resources:
       network: {get_resource: public_network}
       name: {get_param: public_net}
       cidr: {get_param: public_net_cidr}
+      allocation_pools: {get_param: public_net_allocation_pools}
       gateway_ip: null
       enable_dhcp: false