feat: SpeedChart plot visibility toggle

[uFloppyDisk]

Implements feature request #283 Users can individually toggle visibility of speed, accuracy, and complexity scatter-plots by clicking the corresponding coloured markers under the "Typing Speed" chart or "solo" the given plot by hovering over the corresponding marker.

[semanticdiff-com[bot]]

Review changes with  

Changed Files

File	Status
packages/keybr-chart/lib/Marker.tsx	59% smaller
packages/keybr-chart/lib/SpeedChart.tsx	44% smaller
packages/page-profile/lib/profile/SpeedChartSection.tsx	40% smaller
packages/keybr-chart/lib/Marker.module.less	Unsupported file format