Allow users to set Kaleido path via environment variable #407

Job	Run time
Clippy	2m 53s
Tests (ubuntu-latest)	1m 52s
Tests (windows-latest)	4m 30s
Code Coverage	2m 17s
Tests (macos-latest)	9m 30s
Build Examples (3d_charts)	22s
Rustfmt	16s
Build Examples (basic_charts)	26s
semver	35s
Build Examples (custom_controls)	23s
Build Examples (financial_charts)	26s
Build Wasm Examples (wasm-yew-minimal)	47s
Build Examples (images)	38s
Build Examples (kaleido)	1m 11s
Build Examples (maps)	22s
Build Examples (ndarray)	22s
Build Examples (scientific_charts)	22s
Build Examples (shapes)	24s
Build Examples (subplots)	22s
	27m 58s

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