Update Sigma Reference Links to Sigma Project

[Cyb3rWard0g]

Several rules were created here and contributed to the Sigma project. Initially the idea was to keep the rules in this repo and at the same time contribute them to Sigma. However, we never got around to update the links to the sigma project.

Example:

• Playbook: https://threathunterplaybook.com/notebooks/windows/04_privilege_escalation/WIN-200902020333.html
• Local Sigma rule: https://github.com/OTRF/ThreatHunter-Playbook/blob/master/signatures/sigma/win_scrcons_remote_wmi_scripteventconsumer.yml
• Sigma Rule: https://github.com/SigmaHQ/sigma/blob/master/rules/windows/builtin/security/win_scrcons_remote_wmi_scripteventconsumer.yml