As a user, I can select Xray issue types to add in the project settings page

As a user, I can select Xray issue types to add in the project settings page, in order to easily support configuring the different project organization scenarios as mentioned in: 

[http://confluence.xpand-addons.com/display/XRAY/Project%27s+Organisation]

For this, whenever the user selects "Add Xray Issue Types", he should be able to select which Xray issue types to add from a confirmation dialog before submiting the action. All Xray issue types should be selected by default.