Default confidence level

[MVrachev]

Is your feature request related to a problem? Please describe.
Right now if a linter doesn't provide a confidence level on its issues we give a "warning" level of the issue as a whole that doesn't feel correct because there can be serious problems marked as a warning.

Describe the solution you'd like
Based on the severity to give a better conclusion for the issue overall severity.

[MVrachev]

TSLint doesn't provide "confidence level": webschik/tslint-config-security#19