Add `plotly_static` `async` API #74

Job	Run time
Build Wasm Examples (callback-example)	1m 1s
Clippy	4m 3s
Build Wasm Examples (basic)	57s
semver	1m 20s
Code Coverage	11s
Tests (ubuntu-latest, chrome, plotly_ndarray,plotly_image,static_export_default,debug)	3m 18s
Tests (ubuntu-latest, firefox, plotly_ndarray,plotly_image,static_export_geckodriver,static_expor...	3m 26s
Tests (macos-latest, chrome, plotly_ndarray,plotly_image,static_export_default,debug)	2m 56s
Rustfmt	15s
Build Examples (3d_charts)	33s
Tests (windows-latest, chrome, plotly_ndarray,plotly_image,static_export_chromedriver,debug)	6m 55s
Build Examples (basic_charts)	28s
Build Examples (custom_controls)	30s
Build Examples (customization/density_mapbox_example)	31s
Build Examples (customization/consistent_static_format_export)	1m 32s
Build Examples (customization/multiple_plots_example)	40s
Build Examples (maps)	45s
Build Examples (images)	49s
Build Examples (kaleido)	1m 16s
Build Examples (financial_charts)	39s
Build Examples (ndarray)	32s
Build Examples (scientific_charts)	43s
Build Book	2m 21s
Build Examples (shapes)	45s
Build Examples (statistical_charts)	50s
Build Examples (subplots)	36s
Build Examples (themes)	29s
	38m 21s

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