Added holidays for Austria, Norway, and Juneteenth in US

Added holidays for Austria
Added holidays for Norway
Added Juneteenth holiday in US with additional setting for "in lieu" holiday before/after weekend
Fixed RelativePos columns (negative/positive were inverted compared to documentation)
Data type changed to Date instead of Date/Time for Power BI (internal is always DateTime, this is just additional metadata only for Power BI)
Fixed small typos in comments

Author: marcosqlbi