Update urls in documentation from ecosystem to new github pages location

[woodsp-ibm]

There are a number of files with links to the docs in qiskit.org/ecosystem that need updating to the new location as follow-up after #311

• setup.py
• readme.md

and also

• a number of tutorial notebooks

and I listed this separately since the notebooks have links to Algorithms and Optimization for which maybe its better to wait until they are all migrated off ecosystem and update them just the once. The redirects will suffice for now.