Feature/expose_loca_strings expose_locale_maps options

[defuncart]

Adds the options for expose_loca_strings and expose_locale_maps. Resolves #27.

expose_loca_strings

flappy_translator:
  expose_loca_strings: true

/// Returns a map of key-locastring for the selected locale
///
/// ```dart
/// {
///   'test': 'Hello world!',
/// }
/// ```
Map<String, String> get locaStrings => _localizedValues;

expose_locale_maps

flappy_translator:
  expose_locale_maps: true

/// Returns a map of loca maps per locale
///
/// ```dart
/// {
///   'en': {'test': 'Hello world!'},
///   'de_CH': {'test': 'Hallo welt!'},
/// }
/// ```
Map<String, Map<String, String>> get localeMaps => _allValues;

[defuncart]

@chang-ran Please let me know if this would solve your issue. This can be tested as follows:

flappy_translator:
   git:
        url: https://github.com/smartnsoft/FlappyTranslator
        ref: feature/options-all-strings-all-locales

[chang-ran]

I have test this branch and the localeMaps can perfectly solve my problem !

[defuncart]

Updated PR so that locaStrings and localeMaps are copies of original data, otherwise loca strings could be accidentally changed.

/// Returns a map of key-locastring for the current locale
  ///
  /// ```dart
  /// {
  ///   'test': 'Hello world!',
  /// }
  /// ```
  Map<String, String> get locaStrings => Map<String, String>.from(_localizedValues);

  /// Returns a map of loca maps per locale
  ///
  /// ```dart
  /// {
  ///   'en': {'test': 'Hello world!'},
  ///   'de': {'test': 'Hallo welt!'},
  /// }
  /// ```
  Map<String, Map<String, String>> get localeMaps {
    final returnMap = <String, Map<String, String>>{};
    _allValues.forEach(
      (key, value) => returnMap[key] = Map<String, String>.from(value),
    );
    return returnMap;
  }