* feat(obj scroll):subdivide LV_OBJ_FLAG_SCROLL_CHAIN into ...CHAIN_HOR and ...CHAIN_VER
* feat(roller):open the horizontal scroll chain
* chore(docs):improve the description of scroll chain
* - renamed lv_obj_get_id(obj) to lv_obj_get_index(obj).
- added lv_obj_move_to_index(obj, index).
* automatic review comment fixed
* removed unused variable
* review issue
* restored deprecated function in header, otherwise Build Micropython with LVGL submodule / build (pull_request) failes
* moved deprecated lv_obj_get_child_id() back to lv_obj_tree.h, otherwise Micropython will not build
* inline function did not work
* made deprecated function 'static inline'
* and now also inline
* move static inline function to lv_api_map.h again
* removed lv_obj_move_up/down
* changed log to warning for deprecated function
* redefined lv_obj_move_foreground(obj) and lv_obj_move_background(obj) as inline functions now calling lv_obj_move_to_index(obj, index).
- lv_obj_swap(obj1, obj2) added. (#2461)
* - small with unneeded lv_obj_invalidate() fix in lv_obj_move_foreground() and lv_obj_move_background()
- added lv_obj_move_up() and lv_obj_move_down()
- used new functions in sample 2
- used lv_obj_swap() to shuffle (turn around) list
* solved build error
* added top and bottom buttons in sample
Add lv_<widget>_draw_part_type_t to widgets to precisly describe the hooked drawings.
Also add class_p element to lv_obj_draw_part_dsc_t to show what widgets lv_<widget>_draw_part_type_t needs to be used.
Related to: https://forum.lvgl.io/t/how-to-add-minor-division-lines-to-a-chart/5366/
