feat(model): add spm and bpe mode in spm trainer

[boss-chanon]

Why this PR

Make spm_trainer can switch between spm and bpe mode for train sentencepiece tokenizer

Changes

• spm_trainer can select mode for train
• add and token when train sentencepiece finish
• use eos_token_id separator sentence when tokenize sentence instead 0

Related Issues

Close #

Checklist

• [ ] PR should be in the Naming convention
• [ ] Assign yourself in to Assigneees
• [ ] Tag related issues
• [ ] Constants name should be ALL_CAPITAL, function name should be snake_case, and class name should be CamelCase
• [ ] complex function/algorithm should have Docstring
• [ ] 1 PR should not have more than 200 lines changes (Exception for test files). If more than that please open multiple PRs
• [ ] At least PR reviewer must come from the task's team (model, eval, data)