Added functionality to return { label: <country.label>, value: <country.value> } and tests with native support

[Gorsargs]

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[Gorsargs]

getCountryByLabel()
getCountryByValue()
One may want to get a country object of a specific country, these are the methods

Usage
countries.getCountryByLabel('Taiwan, Province of China') // { label: 'Taiwan, Province of China', value: 'TW' }
countries.getCountryByValue('TW') // { label: 'Taiwan, Province of China', value: 'TW' }

Native Usage
countries.native().getCountryByLabel('Taiwan, Province of China') // { label: '臺灣', value: 'TW' }
countries.native().getCountryByValue('TW') // { label: '臺灣', value: 'TW' }