Send Push dialog: allow user to select platform specific options

The dialog should help user to create a message that would test platform specific features:

• sounds, badges
• windows stuff, simplepush

The dialog should show only the features that are enabled for the given application.

The dialog should provide auto-completion for values like enumerations, it should be accompanied with a tooltip stating what value can be provided and finally it can link to documentation where specifics of the given feature are discussed.