[SPARK-2125] Add sort flag and move sort into shuffle implementations

This patch adds a sort flag into ShuffleDependecy and moves sort into hash shuffle implementation.

Moving sort into shuffle implementation can give space for other shuffle implementations (like sort-based shuffle) to better optimize sort through shuffle.

Author: jerryshao <saisai.shao@intel.com>

Closes #1210 from jerryshao/SPARK-2125 and squashes the following commits:

2feaf7b [jerryshao] revert MimaExcludes
ceddf75 [jerryshao] add MimaExeclude
f674ff4 [jerryshao] Add missing Scope restriction
b9fe0dd [jerryshao] Fix some style issues according to comments
ef6b729 [jerryshao] Change sort flag into Option
3f6eeed [jerryshao] Fix issues related to unit test
2f552a5 [jerryshao] Minor changes about naming and order
c92a281 [jerryshao] Move sort into shuffle implementations