Declare backreference one-to-one association (dependency->master)

[shturec]

Currently, the one-to-one association is always in master->dependency direction. There is no way to infer the direction of one-to-one association using the current association configuration properties and in this way it is not possible to define a read-only 'back reference' association to a master entity. It is always treated as 'forward reference'.
A property dedicated to 'one-to-one' association configurations, such as 'direction', and enumeration of possible values (for back and forth direction) is a possible solution in this case.