Old logo and broken URLs in notebook 01-data-analysis-at-scale.ipynb

[avriiil]

The "Dask in the Cloud" blog links to the notebook 01-data-analysis-at-scale.ipynb. I noticed a few issues with this notebook:

1. It contains the old Coiled logo
2. 3 of the URLs (to Coiled and Dask) don't function.

Intro:
"Coiled" and "free Beta here"

Section 2:
"Dask"

Section 3:
"Coiled"