feat: Add support for severity threshold [CFG-1991]

[ofekatr]

• Follows CONTRIBUTING rules

What does this PR do?

• Adds support for the --severity-threshold flag, so that if the user specifies a value, the results returned by the Policy Engine filtered according to the specified severity.

Where should the reviewer start?

src/cli/commands/test/iac/v2/index.ts

Notes

• This PR should be merged after this PR.

How should this be manually tested?

• Prepare a snyk-iac-test binary that includes the functionality from this PR.
• Run SNYK_IAC_POLICY_ENGINE_PATH=<path-to-binary> snyk-dev iac test --experimental --severity-threshold=medium
• Ensure all of the displayed issues are with severity of medium or above.
• Run SNYK_IAC_POLICY_ENGINE_PATH=<path-to-binary> snyk-dev iac test --experimental --severity-threshold=critical
• Ensure all of the displayed issues are with severity of critical
• Run SNYK_IAC_POLICY_ENGINE_PATH=<path-to-binary> snyk-dev iac test --experimental --severity-threshold=wrong -d
• Ensure the Test Engine responded with an error for the invalid severity threshold value, and did not return any results.

Any background context you want to provide?

Once the new iac test command is able to produce output based on the results of the Policy Engine, the user might want to see only issues of a certain severity. Similarly to the current implementation, the Policy Engine defines four levels of severity. The iac test command should support the --severity-threshold flag, read the value provided by the user (if any), and filter out the results generated by the Policy Engine to only include the vulnerabilities with the specified severity or higher.

What are the relevant tickets?

• CFG-1991

Screenshots

[github-actions]

	Warnings
⚠️	You've modified files in src/ directory, but haven't updated anything in test folder. Is there something that could be tested?

Generated by 🚫 dangerJS against 6833389

[YairZ101]

notice that if your PR will get merged after this one, you'll also need to add the errors you've added to the relevant places.

[ofekatr]

@YairZ101 Could you elaborate on where the errors should be added to?

[YairZ101]

Could you elaborate on where the errors should be added to?

src/cli/commands/test/iac/local-execution/types.ts - to add the error code (similar to what we did up until now)
src/lib/iac/test/v2/errors.ts - to add the user message to the relevant error (this part is new)

[ofekatr]

@YairZ101 The user error was added 👍