Update intersphinx links and others

[woodsp-ibm]

Summary

Updates links away from qiskit.org to the new locations for the docs

Fixes #135

#124 : I update all links but Aer for #124 as Aer is not yet done. This amounts to a couple of links in each of the 01 and 03 tutorials that will need to wait on relocated docs for Aer.

Details and comments

Now that all the applications and the algorithms docs are deployed on github pages this updates the intersphinx links, in conf.py, and also urls that are coded directly in other places such as the readme and tutorials.

Note that the current theme is still emitting a link to qiskit.org/ecosystem, but that will get redirected for now until such time as Qiskit/qiskit_sphinx_theme#588 is resolved and new docs are generated with such an updated theme and re-deployed.

[coveralls]

Pull Request Test Coverage Report for Build 7747789130

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 90.666%

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Totals
Change from base Build 7670232715:	0.0%
Covered Lines:	6489
Relevant Lines:	7157

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💛 - Coveralls

[ElePT]

LGTM, thanks for keeping on top of the redirects/docs changes. I'll keep an eye for the Aer docs too.