fix: Fixed support of characters out of latin-1 in page synthesis

[fg-mindee]

This PR fixes the page synthesis feature. Up until now, we have relied on the support of text drawing using Pillow. However as pointed out by #495, this support is limited.

This snippet crashes:

from PIL import Image, ImageDraw
img = Image.new('RGB', (100, 100), color=(255, 255, 255))
d = ImageDraw.Draw(img)
d.text((0, 0), '€', fill=(0, 0, 0))

this PR changes this by catching the UnicodeEncodeError and normalizing the string as follows:

from PIL import Image, ImageDraw
from unidecode import unidecode
img = Image.new('RGB', (100, 100), color=(255, 255, 255))
d = ImageDraw.Draw(img)
d.text((0, 0), unidecode('€'), fill=(0, 0, 0))  #  <--- over HERE

Please note that in doing so, some string will be synthesized with different length cf the snippet below:

In [1]: from unidecode import unidecode
In [2]: print(unidecode('€'))
EUR

Closes #495

Any feedback is welcome!

[charlesmindee]

Thanks for that!