MSRC Severity Fix

[gitBalla]

Among some individualized fixes to my own environment (formatting, disabling auto-update, and removing auto-deploy), there are some useful fixes here for the inaccurate reporting of MSRC severity 'critical'. The old script only checked 'hidden' and 'available', and categorized everything else as 'optional'. This version checks the MSRC severity as expected, and adds the 'important' category to suit the new functionality.