Feature -Request integration with OpenCTI

**Additional context**
ThreatMapper is missing features used to connect to an open-source Cyber Threat Intelligence Platform, such as OpenCTI. This feature request can be used used to map vulnerabilities exploited by known malicious actors (i.e APT). Additionally,

**Is your feature request related to a problem? Please describe.**
Similar to Anomali, or ThreatConnect, a novice CTI analyst will have difficulties mapping CRITICAL/HIGH vulnerabilities to a malicious actor (i.e. APT, or UNC) without integration between ThreatMapper and a CTI platform.

**Describe the solution you'd like**
This feature enhancement would allow CTI analysts to prioritize and rank vulnerabilities exploited, and security advisories warning to patch vulnerabilities commonly propagated by malicious actors

**Describe alternatives you've considered**

MITRE ATT&CK
ThreatConnect
Anomali ThreatStrem
Securonix

**Components/Services**

- [ ] UI/Frontend
- [ ] API/Backend
- [ ] Agent
- [ ] Deployment/YAMLs
- [ ] CI/CD Integration
- [x] Other (specify) - Support for OpenCTI Connectors

**Additional context**
https://www.opencti.io/en/
https://github.com/OpenCTI-Platform
https://github.com/OpenCTI-Platform/connectors