Accept Readonly* arguments

[mshustov]

I often use readonly types in the app to ensure immutable data. I have a hard time passing a read-only argument to a Click-Ui component since an immutable type is a subset of a mutable one. I'd suggest refactoring public interfaces to accept readonly types (for example, ReadonlyArray) instead of mutable ones. For example, in Select

click-ui/src/components/Select/MultiSelect.tsx

Lines 11 to 13 in 9ab8c42

	defaultValue?: Array<string>;
	onSelect?: (value: Array<string>, type?: SelectionType) => void;
	value?: Array<string>;