[New Integration] Censys

# Integration release checklist

This checklist is intended for integrations maintainers to ensure consistency
when creating or updating a Package, Module or Dataset for an Integration.

### All changes

- [ ] Change follows the [contributing guidelines](https://github.com/elastic/integrations/blob/main/CONTRIBUTING.md)
- [ ] Supported versions of the monitoring target are documented
- [ ] Supported operating systems are documented (if applicable)
- [ ] Integration or [System tests](https://github.com/elastic/elastic-package/blob/master/docs/howto/system_testing.md) exist
- [ ] Documentation exists, [useful guidelines](https://github.com/elastic/integrations/blob/main/docs/documentation_guidelines.md) to follow
- [ ] Fields follow [ECS](https://github.com/elastic/ecs) and [naming conventions](https://www.elastic.co/guide/en/beats/devguide/master/event-conventions.html)
- [ ] At least a manual test with ES / Kibana / Agent has been performed.
- [ ] Required Kibana version set to: