feat(BulletChart): Add Thresholds to Legend

[jeff-phillips-18]

Provides the ability to add Threshold items to the legend if either text or a function is provided.

[patternfly-build]

PatternFly-React preview: https://1074-pr-patternfly-react-patternfly.surge.sh

[coveralls]

Pull Request Test Coverage Report for Build 3606

• 3 of 7 (42.86%) changed or added relevant lines in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage decreased (-0.06%) to 82.042%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
packages/patternfly-3/patternfly-react/src/components/Chart/BulletChart/BulletChart.js	3	7	42.86%

Totals
Change from base Build 3605:	-0.06%
Covered Lines:	4265
Relevant Lines:	4915

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💛 - Coveralls

[dlabrecq]

Looks good. Thanks, Jeff!

[dtaylor113]

I'm a little confused. Should the bar turn orange and/or red when over Warning or Error thresholds...like the arc does in gauge charts?

[jeff-phillips-18]

No, the bar remains the same. The threshold lines are used as indicators. See https://www.patternfly.org/pattern-library/data-visualization/bullet-chart/#design

[dtaylor113]

No, the bar remains the same. The threshold lines are used as indicators. See https://www.patternfly.org/pattern-library/data-visualization/bullet-chart/#design

Just concerned, because on that page it has:

What denotes ''poor, good, excellent" for the bars?

[jeff-phillips-18]

That would be up to the application to decide. That text is meant for the range bars.