feat: automate account deletion (#11406)

- Automate the deletion of accounts that have requested deletion via
account settings.
- Add a Sidekiq job that runs daily to find accounts that have requested
deletion and have passed the 7-day window.
- This job deletes the account and then soft-deletes users if they do
not belong to any other account.
- This job also sends an email to the Chatwoot instance admin for
compliance purposes.
- The Chatwoot instance admin's email is configurable via the
`CHATWOOT_INSTANCE_ADMIN_EMAIL` global config.

---------

Co-authored-by: Sojan Jose <sojan@pepalo.com>

app/views/mailers/administrator_notifications/account_compliance_mailer/account_deleted.liquid

@@ -0,0 +1,30 @@
+<p>Hello,</p>
+
+<p>This is a notification to inform you that an account has been permanently deleted from your Chatwoot instance.</p>
+
+<p>
+  <strong>Chatwoot Installation:</strong> {{ meta.instance_url }}<br>
+  <strong>Account ID:</strong> {{ meta.account_id }}<br>
+  <strong>Account Name:</strong> {{ meta.account_name }}<br>
+  <strong>Deleted At:</strong> {{ meta.deleted_at }}<br>
+  <strong>Marked for Deletion at:</strong> {{ meta.marked_for_deletion_at }}<br>
+  <strong>Deletion Reason:</strong> {{ meta.deletion_reason }}
+</p>
+
+{% if meta.deleted_user_count > 0 %}
+<p>
+  <strong>Deleted Users ({{ meta.deleted_user_count }}):</strong><br>
+  {% for user in meta.soft_deleted_users %}
+    User ID: {{ user.user_id }}, Email: {{ user.user_email }}{% unless forloop.last %}<br>{% endunless %}
+  {% endfor %}
+</p>
+{% else %}
+<p>
+  <strong>Deleted Users:</strong> None
+</p>
+{% endif %}
+
+<p>This email serves as a record for compliance purposes.</p>
+
+<p>Thank you,<br>
+Chatwoot System</p>