Allow to filter bandit warnings on severity or confidence

Both options are available on bandit command:

  -l, --level           report only issues of a given severity level or higher
                        (-l for LOW, -ll for MEDIUM, -lll for HIGH)
  -i, --confidence      report only issues of a given confidence level or
                        higher (-i for LOW, -ii for MEDIUM, -iii for HIGH)

We could just blindly add this or think about porting that to the common library and filter on the normalized output for every analyzers 🤔