add draft OpenAssistant OASST1 data notebook (LAION-AI#2551)

- minimal little notebook as a sort of "Getting Started" Notebook for
the [dataset](https://huggingface.co/datasets/OpenAssistant/oasst1)

Author: andrewm4894

notebooks/openassistant-oasst1/README.md

@@ -0,0 +1,7 @@
+# Open Assistant - OASST1 Dataset Notebooks
+
+This repository contains some helper notebooks for playing around with the
+[Open Assistant - OASST1 Dataset](https://huggingface.co/datasets/OpenAssistant/oasst1)
+
+- [`getting-started.ipynb`](./getting-started.ipynb) - Getting started with the
+  dataset.