Improvement/bar width

[boygirl]

This PR:

• Adds barWidth and candleWidth ratios to VictoryBar and VictoryCandlestick respectively. These props should be used in place of width on styles. This change was made because width as it is used in these components is not a standard svg style attribute. This change should reduce confusion.
• Does not deprecate the use of width in styles for VictoryBar or VictoryCandlestick, however, the new props will take precedence.
• Adds a candleRatio prop that works the same was as barRatio
• Cleans up methods and props on Bar and Candle primitive components