Feature [DEV-11788] Dynamic y-axis width for horizontal bars

[jayb]

Summary

Makes three improvements to horizontal bar charts:

• Adds an option to turn on gridlines (vertical light grey lines on the chart)
• Makes the width of the y-axis dynamic when the "Label placement: on date/category axis" option is selected, and positions y-axis labels appropriately.
• Reduces font size of data labels on horizontal bars to match vertical bars.

Testing Steps

This story illustrates the new features. Make the window wider/narrower to see y-axis width resizing.