Enhance the check on aggregation group dimension number

If the dimension number in an aggregation group exceeds the number of "kylin.cube.aggrgroup.max.size" (default 12), Kylin will throw an error saying "Aggregation group <n> has too many dimensions"; User has to remove some dimensions to proceed.

This check adds up the number of mandantory dimensions, hierarchy, joint and normal dimensions; This is too strong. The check should be optimized, all mandantory be treated as 1; all joint dimensions be treated as 2; each hierarchy be treated as N+1; nomal dimensions be 2^N; Control total combination numbers no more than a configured value ("kylin.cube.aggrgroup.max.combination", default 4096).