Fix outdated function api in pillow, add utf8_map in template file

1. replace outdated font.getsize() to font.getbbox() import from Pillow
2. add utf8_map and enable_utf8 in template file

initial release

1. Redefine the template format
2. Add template keyword
3. Encoding option: raw, raw with bounding box, lvgl compression(no pre-filter)