Moving content of notebook_examples to documentation folder

We have in the source a folder called notebook_examples, the content of which should probably be moved to the online documentation:

• Knife edge scan and fluence calculation.ipynb @mercadil
• tim-normalization.ipynb
• XAS and XMCD energy shift investigation.ipynb @lleguy

assigned to @lleguy

mentioned in issue #76 (closed)

marked the checklist item Knife edge scan and fluence calculation.ipynb @mercadil as completed