New module - meraki_mr_l3_firewall (#42328)

* Initial commit for meraki_mr_l3_firewall module

- CRUD functionality for layer 3 firewall rules on the Meraki MR access points
- Complimentary integration test
- Need to add support for SSID lookup

* Added support for specifying SSID name and improved documentation

* Added examples to documentation

* Removed whitespace

test/integration/targets/meraki_mr_l3_firewall/aliases

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+unsupported

test/integration/targets/meraki_mr_l3_firewall/tasks/main.yml

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+# Test code for the Meraki modules
+# Copyright: (c) 2018, Kevin Breit (@kbreit)
+
+# GNU General Public License v3.0+ (see COPYING or https://www.gnu.org/licenses/gpl-3.0.txt)
+---
+- name: Create wireless network
+  meraki_network:
+    auth_key: '{{ auth_key }}'
+    state: present
+    org_name: '{{test_org_name}}'
+    net_name: TestNetWireless
+    type: wireless
+  delegate_to: localhost
+  register: new_net
+
+- set_fact:
+    net: '{{new_net.data.id}}'
+
+- name: Create single firewall rule
+  meraki_mr_l3_firewall:
+    auth_key: '{{ auth_key }}'
+    state: present
+    org_name: '{{test_org_name}}'
+    net_id: '{{net}}'
+    number: 1
+    rules:
+      - comment: Integration test rule
+        policy: allow
+        protocol: tcp
+        dest_port: 80
+        dest_cidr: 192.0.2.0/24
+    allow_lan_access: no
+  delegate_to: localhost
+  register: create_one
+
+- debug:
+    msg: '{{create_one}}'
+
+- assert:
+    that:
+      - create_one.data.0.comment == 'Integration test rule'
+      - create_one.data.1.policy == 'deny'
+
+- name: Enable local LAN access
+  meraki_mr_l3_firewall:
+    auth_key: '{{ auth_key }}'
+    state: present
+    org_name: '{{test_org_name}}'
+    net_id: '{{net}}'
+    number: 1
+    rules:
+    allow_lan_access: yes
+  delegate_to: localhost
+  register: enable_lan
+
+- assert:
+    that:
+      - enable_lan.data.1.policy == 'allow'
+
+- name: Query firewall rules
+  meraki_mr_l3_firewall:
+    auth_key: '{{ auth_key }}'
+    state: query
+    org_name: '{{test_org_name}}'
+    net_id: '{{net}}'
+    number: 1
+  delegate_to: localhost
+  register: query
+
+- debug:
+    msg: '{{query}}'
+
+- assert:
+    that:
+      - query.data.1.comment == 'Wireless clients accessing LAN'
+      - query.data.2.comment == 'Default rule'
+      - query.changed == False
+
+- name: Delete wireless network
+  meraki_network:
+    auth_key: '{{ auth_key }}'
+    state: absent
+    org_name: '{{test_org_name}}'
+    net_id: '{{net}}'
+    number: 1
+  delegate_to: localhost