Removed ShowCapslockWarning-DP, instead introduced CapsLockIcon-DP. This DP takes now an object that allows the developer to show any element he wants as warning icon for enabled CapsLock.

CapsLockWarningText is now of type object in order to have the same behaviour as in CapsLockIcon-DP
Adaption of xaml
Refactoring of DP for better understanding.