feat: Reusable logging, audit and log shipping roles

[karimodm]

Proposed changes

• Added reusable logging/audit playbooks: playbooks/logging/audit_session.yml and playbooks/logging/promtail.yml.
• New role linkorb.polaris.audit_session: installs tlog/auditd, sets log_group, deploys tlog config, assigns shells/groups to admins, ensures auditd running.
• New role linkorb.polaris.promtail_host: installs promtail, adds required groups/dirs, renders simplified promtail config (journal/syslog/auditd scrapes), supports Loki basic auth/labels, ensures service running.
• Role docs/defaults/templates/handlers included for both roles.

[karimodm]

Should we merge this @boite ?

[boite]

/close This PR was reworked as fb231a0 to change roles into layers. That commit is not merged into main yet, that's because it does not correctly set permissions for the session locks.