Import InterCERT Case templates & function_notifier

[Lohuss]

Added:
InterCERT case templates (EN + FR)
Functions based on notifier:

• Compute total time spent on task (effective time spent)
• External access automation (if a domain is entered as customfield, every external users from this domain will have visibility granted)
• Add tag to check if IP observable is public, private or invalid regarding RFC 1918 / 4193 (mainly for futher automations around IPs)