feat(layout): add `LayoutPolar` #91

Job	Run time
Rustfmt	16s
Clippy	1m 51s
semver	46s
Tests (ubuntu-latest, firefox, plotly_ndarray,plotly_image,static_export_geckodriver,static_expor...	10m 16s
Tests (windows-latest, chrome, plotly_ndarray,plotly_image,static_export_chromedriver,debug)	6m 11s
Code Coverage	9s
Tests (ubuntu-latest, chrome, plotly_ndarray,plotly_image,static_export_default,debug)	3m 24s
Tests (macos-latest, chrome, plotly_ndarray,plotly_image,static_export_default,debug)	3m 48s
Build Examples (basic_charts)	35s
Build Examples (customization/consistent_static_format_export)	1m 25s
Build Examples (3d_charts)	34s
Build Examples (customization/density_mapbox_example)	31s
Build Examples (custom_controls)	39s
Build Examples (maps)	37s
Build Examples (financial_charts)	29s
Build Examples (images)	47s
Build Examples (ndarray)	36s
Build Examples (kaleido)	1m 12s
Build Examples (shapes)	35s
Build Examples (customization/multiple_plots_example)	36s
Build Examples (scientific_charts)	31s
Build Examples (themes)	31s
Build Examples (statistical_charts)	32s
Build Book	3m 26s
Build Examples (subplots)	27s
Build Wasm Examples (basic)	49s
Build Wasm Examples (callback-example)	54s
	42m 27s

Provide feedback