Setting the `defaultlocale` should update developmentRegion and knownRegions in pbxproj

[ath0mas]

Feature Request

Motivation Behind Feature

Since #237 adding a defaultlocale="XX" attribute to the widget tag in config.xml allows to set the CFBundleDevelopmentRegion to a different language (in the <project_name>-Info.plist file).

⇒ This same language should also be applied into the pbxproj files of the project and CordovaLib, to replace the hardcoded en from the templates for developmentRegion and knownRegions.

Feature Description

The templates for the project and CordovaLib are used to init the iOS project structure.

With previous #237, the __PROJECT_NAME__-Info.plist file is modified to target CFBundleDevelopmentRegion and replace the hardcoded value of en_US with the language set through defaultlocale.

Same should be done in project pbxproj file and CordovaLib pbxproj file, targeting developmentRegion (+) and knownRegions (+) and replacing the hardcoded value of en there too.

(may require apache/cordova-node-xcode#122?)

Alternatives or Workarounds

Custom script after platform add.

Or should I start a new cordova-plugin to add more defaults like this about locales? (to include this, apache/cordova-android#1396, kelvinhokk/cordova-plugin-localization-strings#65, and more?)