baby_keyboard, add all letters for the current locale.

For now, it also keeps the punctuations that we did not have before (I can remove them if preferred). Also, before the layout was static (as we did not add letters depending on the locale) so all the numbers were always on first row, and then letters. I can probably ensure we have the same first row and then all the letters. I removed backspace, newline and space but I can add them again. For non latin languages, there will be both alphabets so maybe not the best too.

To be discussed more: @huftis @timotheegiet