feat(gridnav): add lv_gridnav (#2911)

* add first implememtation

* Update src/extra/others/gridnav/lv_gridnav.c

Co-authored-by: embeddedt <42941056+embeddedt@users.noreply.github.com>

* minor fix

* add example and minor fixes

* add more examples

* add more examples

* code formatting

* add LV_GRIDNAC_CTRL_SCROLL_FIRST

* code formatting

* add example for list

* add docs

* Misc:  improvements to gridnav docs (#2994)

Co-authored-by: embeddedt <42941056+embeddedt@users.noreply.github.com>
Co-authored-by: Ken Carpenter <62639971+FoundationKen@users.noreply.github.com>

docs/others/gridnav.md

@@ -0,0 +1,60 @@
+```eval_rst
+.. include:: /header.rst 
+:github_url: |github_link_base|/others/gridnav.md
+```
+# Grid navigation
+
+Grid navigation (gridnav for short) is a feature that changes the currently focused child object as arrow keys are pressed.
+
+If the children are arranged into a grid-like layout then the up, down, left and right arrows move focus to the nearest sibling
+in the respective direction.
+
+It doesn't matter how the children are positioned, as only the current x and y coordinates are considered.
+This means that gridnav works with manually positioned children, as well as [Flex](/layouts/flex.html) and [Grid](/layouts/grid.html) layouts.
+
+Gridnav also works if the children are arranged into a single row or column.
+That makes it useful, for example, to simplify navigation on a [List widget](/widgets/extra/list.html).
+
+Gridnav assumes that the object to which gridnav is added is part of a [group](/overview/indev.html#groups). 
+This way, if the object with gridnav is focused, the arrow key presses are automatically forwarded to the object
+so that gridnav can process the arrow keys.
+
+To move the focus to the next widget of the group use `LV_KEY_NEXT/PREV` or `lv_group_focus_next/prev()` or the `TAB` key on keyboard as usual. 
+ 
+If the container is scrollable and the focused child is out of the view, gridnav will automatically scroll the child into view.
+ 
+## Usage
+
+To add the gridnav feature to an object use `lv_gridnav_add(cont, flags)`.
+
+`flags` control the behavior of gridnav:
+- `LV_GRIDNAV_CTRL_NONE` Default settings 
+- `LV_GRIDNAV_CTRL_ROLLOVER`  If there is no next/previous object in a direction, 
+the focus goes to the object in the next/previous row (on left/right keys) or first/last row (on up/down keys 
+- `LV_GRIDNAV_CTRL_SCROLL_FIRST` If an arrow is pressed and the focused object can be scrolled in that direction
+then it will be scrolled instead of going to the next/previous object.  If there is no more room for scrolling the next/previous object will be focused normally 
+
+`lv_gridnav_remove(cont)` Removes gridnav from an object.
+
+## Focusable objects
+
+An object needs to be clickable or click focusable (`LV_OBJ_FLAG_CLICKABLE` or `LV_OBJ_FLAG_CLICK_FOCUSABLE`) 
+and not hidden (`LV_OBJ_FLAG_HIDDEN`) to be focusable by gridnav.
+
+
+## Example
+
+```eval_rst
+
+.. include:: ../../examples/others/gridnav/index.rst
+
+```
+## API
+
+
+```eval_rst
+
+.. doxygenfile:: lv_gridnav.h
+  :project: lvgl
+
+```

docs/others/index.md

@@ -12,5 +12,6 @@
    
    snapshot
    monkey
+   gridnav
 ```