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.

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

config/schedule.yml

@@ -39,3 +39,10 @@ process_stale_contacts_job:
   cron: '30 04 * * *'
   class: 'Internal::ProcessStaleContactsJob'
   queue: housekeeping
+
+# executed daily at 0100 UTC
+# to delete accounts marked for deletion
+delete_accounts_job:
+  cron: '0 1 * * *'
+  class: 'Internal::DeleteAccountsJob'
+  queue: scheduled_jobs