Add Custom rules to SAST scan

[attiasas]

• All tests passed. If this feature is not already covered by the tests, I added new tests.
• I used npm run format for formatting the code before submitting the pull request.

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Add Custom rules to the SAST scan in your workspace

1. Prepare a custom json rules file with your rules:

[
  {
    "name": "custom-rule",
    "message": "User-controlled data used as argument to math.sqrt",
    "finder": {
      "type": "FlowFinder",
      "sources": {
        "type": "calls",
        "names": [
          "input"
        ]
      },
      "sinks": {
        "type": "calls",
        "names": [
          "math.sqrt"
        ]
      }
    },
    "cwe": null,
    "description": "User-controlled square root",
    "severity": "high",
    "tags": []
  }
]

2. Provide the Absolute path to the user custom rule file at the extension's new configuration.

3. Rescan your workspace.

[hadarshjfrog]

I see user_rules is assigned here - but where is it used? who calls this param inside Configuration object?

[attiasas]

@hadarshjfrog, The configuration value is coming from the settings in the vscode as shared at the details

The value is than fetched using Configuration.getSastCustomRulesPath and we pass it to the SAST scanner that uses it while running. (user_rules is a new attribute in the scanner config)