This will allow to utilize the native return keys provided by most mobile
platforms, to indicate what kind of action pressing it will result in,
such as performing a search, a navigation, moving on to the next input
field or just closing the keyboard.
[ChangeLog][QtCore][Global] Added ReturnKeyType enum allowing for fine-grained
control of the platform's on screen keyboard return key
Change-Id: I6a691045ad6970e6893f23773b2449a7bafd98fc
Reviewed-by: Richard Moe Gustavsen <richard.gustavsen@theqtcompany.com>