Establish late-bound mode for Binding using property declarations

The same way Connections has a late-bound mode using function declarations of a specific form, Binding should have a late-bound mode using property declarations of a specific form. Instead of the current:

Binding {
    foo.bar: some + expression
}

You'd write:

Binding {
    target: foo
    property int bar: some + expression
}

If the "property" property is not given, Binding would then automatically synchronize any declared properties with equivalent properties of the target.

An interesting question is how to handle the type here. Does the declaration only match if the type is the same or do we allow coercions? Connections does coerce signal arguments. So that would be an argument for allowing coercion here, too.