support ATS third party keys

<access> tag attributes in config.xml currently do not support all of possible keys.
support for the following third party related keys is missing:
// Keys to describe your app’s intended network behavior for
// domains whose security attributes you don't control
NSThirdPartyExceptionAllowsInsecureHTTPLoads : Boolean
NSThirdPartyExceptionRequiresForwardSecrecy : Boolean
NSThirdPartyExceptionMinimumTLSVersion : String

could you add support for these as well?
or is there maybe already a special reason why they are not supported?

files that would need to be modified for support:
cordova-common/src/ConfigParser/ConfigParser.js
cordova-lib/src/cordova/metadata/ios_parser.js

full set of keys can be seen at:
https://developer.apple.com/library/ios/documentation/General/Reference/InfoPlistKeyReference/Articles/CocoaKeys.html