Issue #2944087 by John Cook, andileco: Add polar plotting to Highcharts graphs

includes/charts.pages.inc

...es/charts_api_example/src/Controller/ChartsApiExample.php

modules/charts_blocks/src/Plugin/Block/ChartsBlock.php

modules/charts_highcharts/README.txt

modules/charts_highcharts/charts_highcharts.libraries.yml

...s/charts_highcharts/src/Charts/HighchartsChartsRender.php

modules/charts_highcharts/src/Plugin/chart/Highchart.php

modules/charts_highcharts/src/Settings/Highcharts/Chart.php

src/Form/ChartsConfigForm.php