fix(donut-pct-chart): Add tooltip attribute

[TheRealJon]

Description

Add a tooltip attribute to the donut-pct-chart component which allows for a selection between 3 preset tooltip formats: Fixes https://github.com/patternfly/angular-patternfly/issues/671

Screen Shots

Percent Format tooltip = 'percent' (default)

Amount Format tooltip = 'amount'

Both Format tooltip = 'both'

PR Checklist

• [x] Unit tests are included
• [X] Screenshots are attached (if there are visual changes in the UI)
• [X] A Designer (@beanh66) is assigned as a reviewer (if there are visual changes in the UI)
• [X] A CSS rep (@cshinn) is assigned as a reviewer (if there are visual changes in the UI)

[beanh66]

@TheRealJon Thanks, the percent format and the amount format look great. I was wondering if we could make a small adjustment to the format with both. I noticed in the PF Design it shows both with a gap between, something like this: Is it possible to make this change to be more consistent? I attached the design example for reference as well.

[TheRealJon]

@beanh66 I adjusted the format to match your screen shot:

[TheRealJon]

@dtaylor113 @beanh66 Could you approve again? I just added some unit tests for the tooltip.