Improve Crowdsec notification format

[stephdl]

Proposed solution

Enhance email notifications generated by modules such as ns8-crowdsec by including the fully qualified domain name (FQDN) and module ID within the email properties. Additionally, improve the HTML formatting of the email template and introduce an unban link for easier access and management.

Alternative solutions

Continue using the current email notification system, which lacks FQDN, module ID, and streamlined management features such as direct unban links.

Additional context

This enhancement was proposed and implemented in NethServer/ns8-crowdsec#92. Screenshots of the improved email template are available in the linked PR:

[stephdl]

QA

target is 1.0.18-dev.1

• case 1
  install a stable version, configure smarthost, configure recipient to send email on a real server on internet (we need attackers)
  see emails of bans are coming to you
  upgrade to 1.0.18-dev.1
  by default you will have one email by day or once the notification threshold has been hit. Either you spent 24hours or you can lower the notification threshold to get more often emails (set to 1 and you will get back to the previous behavior, one ban one email)
  no issue expected

• case 2
  install a stable version, do not configure email and smarthost on a real server on internet (we need attackers)
  upgrade to testing
  configure recipient and smarthost
  wait after emails
  no issue expected

• case3
  check the received email we have tried to improve the informations inside

  • it is html email with css.
  • We state on the FQDN of the crowdsec instances, the module ID and a button to access to the unban page of the crowdsec instance.
  • We only list the number of decisions and when the first decision has started