LVGL allow access to lv.LAYOUT_GRID and lv.LAYOUT_FLEX

[s-hadinger]

Description:

LVGL allow access to lv.LAYOUT_GRID and lv.LAYOUT_FLEX. The mapping requires a helper accessor function since they are not constants.

Example of script:

lv.start()

hres = lv.get_hor_res()       # should be 320
vres = lv.get_ver_res()       # should be 240

var col_dsc = lv.coord_arr([70, 70, 70, lv.GRID_TEMPLATE_LAST])
var row_dsc = lv.coord_arr([50, 50, 50, lv.GRID_TEMPLATE_LAST])

# Create a container with grid
var cont = lv.obj(lv.scr_act())
cont.set_style_grid_column_dsc_array(col_dsc, 0)
cont.set_style_grid_row_dsc_array(row_dsc, 0)
# cont.set_size(300, 220)

cont.set_size(hres - 10,vres - 10)
cont.set_pos(10,30)

cont.center()
cont.set_layout(lv.LAYOUT_GRID) # issue

for i:0..9
    var col = i % 3
    var row = i / 3

    var obj = lv.btn(cont)
    # Stretch the cell horizontally and vertically too
    # Set span to 1 to make the cell 1 column/row sized
    obj.set_grid_cell(lv.GRID_ALIGN_STRETCH, col, 1,
                      lv.GRID_ALIGN_STRETCH, row, 1) # issue

    var label = lv.label(obj)
    label.set_text("c" +str(col) +  "r" +str(row))
    label.center()
end

Checklist:

• The pull request is done against the latest development branch
• Only relevant files were touched
• Only one feature/fix was added per PR and the code change compiles without warnings
• The code change is tested and works with Tasmota core ESP8266 V.2.7.4.9
• The code change is tested and works with Tasmota core ESP32 V.2.0.6
• I accept the CLA.

NOTE: The code change must pass CI tests. Your PR cannot be merged unless tests pass