feat: nested object scopes

[QuiiBz]

Closes #19

The current syntax for writing locale is:

export default {
  hello: 'Hello',
  welcome: 'Hello {name}!',
  'about.you': 'Hello {name}! You have {age} yo',
  'scope.test': 'A scope',
  'scope.more.test': 'A scope',
  'scope.more.param': 'A scope with {param}',
  'scope.more.and.more.test': 'A scope',
  'missing.translation.in.fr': 'This should work',
} as const

And you're now able to write locales using nested objects:

export default {
  hello: 'Hello',
  welcome: 'Hello {name}!',
  about: {
    you: 'Hello {name}! You have {age} yo',
  },
  scope: {
    test: 'A scope',
    more: {
      test: 'A scope',
      param: 'A scope with {param}',
      and: {
        more: {
          test: 'A scope',
        },
      },
    },
  },
  missing: {
    translation: {
      in: {
        fr: 'This should work',
      },
    },
  },
} as const