feat: Unstructured elements splitting example

add set threshold

feat: Rolling window splitter

fix: added defaults.  mistral added to layer.py

This involved updating the prompt in llms > base.py to be more reliable.

Also created Notebook 07 to showcase Ollama with dynamic routes.

Ensured that we have default values for attributes name, temperature, llm_name, max_tokens and stream.

User can choose to alter the values that are actually used on the fly via new optional arguments in  __call__.

Also _call_ changed to __call__, in line with other LLMs.

Previously self.name was being used to identify the LLM to be called, but self.name is intended to identify the OllamaLLM instance as an instance of OllamaLLM. So it's now set to "ollama".

feat: openai encoder org id support

fix: Added batches for large dataset training error