feat(opengles): add basic driver for opengles (#6254)

Co-authored-by: Dany Liu <dany.yang.liu@email.com>
Co-authored-by: Gabor Kiss-Vamosi <kisvegabor@gmail.com>

docs/integration/driver/index.rst

@@ -10,3 +10,4 @@ Drivers
     libinput
     X11
     windows
+    opengles

docs/integration/driver/opengles.rst

@@ -0,0 +1,65 @@
+===============================
+OpenGL ES Display/Inputs driver
+===============================
+
+Overview
+--------
+
+| The **OpenGL ES** display/input `driver <https://github.com/lvgl/lvgl/src/drivers/opengles>`__ offers support for simulating the LVGL display and keyboard/mouse inputs in an desktop window created via GLFW.
+| It is an alternative to **Wayland**, **XCB**, **SDL** or **Qt**.
+
+The main purpose for this driver is for testing/debugging the LVGL application in an **OpenGL** simulation window.
+
+Prerequisites
+-------------
+
+The OpenGL driver uses GLEW GLFW to access the OpenGL window manager.
+
+1. Install GLEW and GLFW: ``sudo apt-get install libglew-dev libglfw3-dev``
+
+Configure OpenGL driver
+-----------------------
+
+1. Required linked libraries: -lGL -lGLEW -lglfw
+2. Enable the OpenGL driver support in lv_conf.h, by cmake compiler define or by KConfig
+    .. code:: c
+
+        #define LV_USE_OPENGLES  1
+
+Usage
+-----
+
+.. code:: c
+
+    #include "lvgl/lvgl.h"
+    #include "lvgl/examples/lv_examples.h"
+    #include "lvgl/demos/lv_demos.h"
+
+    int main()
+    {
+        lv_init();
+
+        lv_display_t * disp = lv_glfw_window_create(480, 272);
+
+        lv_indev_t * mouse = lv_glfw_mouse_create();
+        lv_indev_set_group(mouse, lv_group_get_default());
+        lv_indev_set_display(mouse, disp);
+
+        lv_display_set_default(disp);
+
+        LV_IMAGE_DECLARE(mouse_cursor_icon); /*Declare the image file.*/
+        lv_obj_t * cursor_obj;
+        cursor_obj = lv_image_create(lv_screen_active());   /*Create an image object for the cursor */
+        lv_image_set_src(cursor_obj, &mouse_cursor_icon);   /*Set the image source*/
+        lv_indev_set_cursor(mouse, cursor_obj);             /*Connect the image  object to the driver*/
+
+        lv_demo_widgets();
+
+        while (1)
+        {
+            uint32_t time_till_next = lv_timer_handler();
+            lv_delay_ms(time_till_next);
+        }
+
+        return 0;
+    }