`searchTask` has 683 lines of code, `queryTask` has 485 lines of code.
`task.go` contains 4k+ codes including `searchTask` and `queryTask`.
It was so much pain navigating codes of searchTask and queryTask though task.go,
task.go and task_test.go are literaly unreadable.
This PR moves
1. 650+ lines of code of `searchTask` from `task.go` to `task_search.go`.
2. 1.4k+ lines of test code of `searchTask` from `task_test.go` to
`task_search_test.go`.
3. 450+ lines of code of `queryTask` from `task.go` to `task_query.go`.
4. 200+ lines of test code of `queryTask from `task_test.go to
`task_query_test.go`.
This PR also rearrange methods positions of `searchTask` and
`queryTask`:
- Putting the most important methods `PreExecute`, `Execute`, and
`PosExecute` at the beginning of the file.
- Moves interface methods `ID`, `SetID`, `Type`, `BeginTs`, etc.
that nobody cares about to the bottom of the file.
See also: #16298
Signed-off-by: yangxuan <xuan.yang@zilliz.com>
