Add clean_up_tokenization_spaces to config
# What does this PR do?
DRAFT
_The documentation is not available anymore as the PR was closed or merged._<|||||>cc @Narsil <|||||>Also linked to #20846. A follow up PR can now be made to add a simple warning if the default value is set to `True` / put the default value to True<|||||>It seems like no model defaulted to use `cleanup_tokenization_spaces = False` so this should be seamless. Otherwise the tokenizer's `__init__` should be updated