Native Full Join Support

There are many limitation with cube at join level, by default cube adds left join in the query and that is very basic use-case. As we are aware we can do inner join with adding segment or where clause check, but there are many use-case that is not solved due to limitation.

e.g We need FULL OUTER JOIN support, as of now we need to add custom cube with custom sql to do full outer join, but let's assume both tables have many same columns, we need to do manual alias to identify unique column and then expose as dimension. that solution is not scalable, we need to manually change cube schema

if let say there are student, employee 2 different cube, then we need to have mechanism to add full outer join, keeping dimensions in individual files