Feature 2148/replace nivo with recharts radar chart teamskills

[pieperm]

To test:

• Log in as an admin
• Go to REPORTS > Team Skills
• Select some members who have skills
• Select some skills, then run search
• Radar chart should display, and colors should not change unless you refresh the page
• Note: The radar chart seems to work with only 1 skill, but it is not easy to read without the tooltip

This finishes up the work started by @Richardson-e. Adjustments:

• Removed nivo dependency
• Fixed how colors are generated for the radar chart
• Radar chart now displays tooltip with info about the distribution

There are probably additional enhancements we could make for generating the radar chart colors:

• Make sure all generated colors are distinct in hue
• Make sure all generated colors are legible (e.g. yellow, light pastels)
• Allow the user to regenerate all colors or a color of their choosing

Closes #2184