Add the plan node and executor for ACL related query. (#62)

* Add the plan node and executor for create user.

* Add plan node and executor about drop user.

* Fix one lack error.

* Add plan ndoe and executor about update user.

* Add plan node and executor about grant role to user.

* Add plan node and executor about revoke role from user.

* Create the executor by user related plan node.

* Add a macro to process the execution request response.

* Add plan node and executor for change password.

* Add the plan and executor for get roles in account.

* Add plan node and executor for list users.

* Fix the commit lack.

* Add the plan node and executor for list roles in space.

* Add the mock implemantion about ACL related RPC.

* JIRA NB-92

* Add some simple testing about ACL.

* Add the test cases about validator.

* Replace the GET_PLAN by method.

* Provide more clear error mesage for execution query for user/roles.

* Fix the alignment.

* Using the meta::cpp2::RoleType directly.

* Move the object from sentence to plan.

* Revert the create space node.

* Using the sentence from base validator.

* Fix the alignment.

* Replace SINGLE_NODE_PLAN_TEMPLATE by function.

* Remove the unused webservice obj in mock.

* Trigger.

* Make acl node as Single Input Node.

* Fix the append plan not return status.

* Check the top of all plan.

* Change to single dependency node.

* Revert the cmake file change.

* Add validator to show roles and users.

* Check the length limit of username and password.

* Format.

* Uing ng error return.

* Change input to dep.

* Change to ref the sentence field.

* Remove the unused method.

* Remove the extra PlanNode scope.

* Fix the header guard.

* Remove the unused file.

* Add users test cases.

* Remove the extra blank.

* Fix cases.

* Add executor time stat.

* Remove the unused callback.

* Mark the exlain unimplemented.

* Fix compile error.

* Remove the unused file.

* Fix the header guard format.

* Add header guard.