Create a list of settings for the columns of a bar chart.
amColumn(
  color = NULL,
  opacity = NULL,
  strokeColor = NULL,
  strokeWidth = 4,
  cornerRadius = 8
)color of the columns; this can be a color adapter
opacity of the columns, a number between 0 and 1
color of the border of the columns; this can be a color adapter
width of the border of the columns
radius of the corners of the columns
A list of settings for usage in amBarChart
  or amHorizontalBarChart