readme: fix max_length parameter in text generation pipeline

readme: minor fix in intro section

readme: add initial versioN

model: add German GPT-2 model (both PyTorch and TensorFlow weights)

vocab: add vocab (incl. merged) for German GPT-2 model. Vocab was created with Tokenizers library and includes tokenizer configuration

config: add configuration for German GPT-2 model

initial commit