Add equivalent of DOCKER_INSECURE and REGISTRY_INSECURE to container scanning

Why are we doing this work

For feature compatibility with the previous container-scanning analyzer, we need an equivalent of the DOCKER_INSECURE and REGISTRY_INSECURE configuration variables and rename to CS_DOCKER_INSECURE and CS_REGISTRY_INSECURE:

Variable	Default	Description
CS_DOCKER_INSECURE	false	Disable certificate validation when accessing secure Docker registries over HTTPS.
CS_REGISTRY_INSECURE	false	Allow insecure connections (HTTP) to a container registry.

Relevant links

Non-functional requirements

• Documentation: Update variables in doc/user/application_security/container_scanning/index.md
• [-] Feature flag:
• [-] Performance:
• Testing:
  • Test scanner with CS_DOCKER_INSECURE and CS_REGISTRY_INSECURE

Implementation plan

1. Add support for CS_REGISTRY_INSECURE and CS_DOCKER_INSECURE. Default value false. And update documentation for the same.
2. For Trivy add support for the variables here:
   1. CS_DOCKER_INSECURE maps to TRIVY_INSECURE
   2. CS_REGISTRY_INSECURE maps to TRIVY_NON_SSL.