feat(ansible): Add role for managing ingress restrictions

Introduces a new Ansible role `ingress-restrictions` with tasks to manage
ingress restrictions between edge and middle hosts. Also includes necessary
files such as handlers, vars, defaults, and README.

external/sketch/ansible/roles/ingress-restrictions/README.md

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+ingress-restrictions
+=========
+
+This role is used to help reduce the chances for backflip correlation from public ssh keys from tools like Censys.
+
+This will automatically tell middle hosts to only allow connections on port 2222 from edge hosts.
+
+This role only handles the sketch infrastructure as of now.
+
+Requirements
+------------
+
+Once you've ran this in your Sketch infrastructure, you will need to grab the IP Addresses or IP Address range from your middles and add them to your OCI/AWS infrastructure manually.
+
+Whenever we do the grand restructure, this should be done automatically for you everywhere.
+
+Example Playbook
+----------------
+
+```yml
+- hosts: all
+  roles:
+    - ingress-restrictions
+```

external/sketch/ansible/roles/ingress-restrictions/meta/main.yml

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+dependencies: []

external/sketch/ansible/roles/ingress-restrictions/tasks/main.yml

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+---
+# tasks file for ingress-restrictions
+
+- name: Set fact for 'edge' hosts
+  set_fact:
+    is_edge_host: true
+  when: "'edge' in inventory_hostname"
+
+- name: Gather Edge IPs into a dictionary
+  set_fact:
+    edge_ips_dict: >-
+      {{
+        edge_ips_dict | default({}) | combine(
+          { item: hostvars[item]['host_ip_address'] }
+        )
+      }}
+  loop: "{{ groups['all'] }}"
+  when: hostvars[item]['is_edge_host'] is defined and hostvars[item]['is_edge_host']
+  delegate_to: localhost
+
+- name: Allow port 2222 from Edges to Middles
+  ufw:
+    rule: allow
+    port: 2222
+    from_ip: "{{ item.value }}"
+  with_items: "{{ edge_ips_dict | dict2items }}"
+  when: "'middle' in inventory_hostname"
+
+- name: Deny port 2222
+  ufw:
+    rule: deny
+    port: 2222
+  when: "'middle' in inventory_hostname"

external/sketch/ansible/roles/ingress-restrictions/tests/inventory

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+localhost
+

external/sketch/ansible/roles/ingress-restrictions/tests/test.yml

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+---
+- hosts: localhost
+  remote_user: root
+  roles:
+    - ingress-restrictions