[Optional] Provide TFAutoModels for different head types

[MarkusSagen]

When creating a TF Resuable SavedModel, it would be great to use to some extent be able to not need to create your own custom model for every model head

The basic example covers currently covers tokenizer and a base MLM model.
It would be great if to provide a TFTAutoModelForSequenceClassification, that creates a reusable saved model for with tokenizer and model. This could then be extended to every transformer head

Can be done without major changes

• "TFAutoModel"
• "TFAutoModelForMultipleChoice"
• "TFAutoModelForSequenceClassification"
• "TFAutoModelForPreTraining"
• "TFAutoModelForTokenClassification"
• "TFAutoModelWithLMHead"

Require Different changing Tokenizer masking?

• "TFAutoModelForCausalLM"
• "TFAutoModelForMaskedLM"
• "TFAutoModelForSeq2SeqLM"

Require tokenizer to except multiple inputs

• "TFAutoModelForQuestionAnswering"
• "TFAutoModelForTableQuestionAnswering"