Deprecate qiskit-ibm-provider

[kt474]

Summary

Fixes #745

Replacing jupyter-execute with code-block because of issues with jupyter sphinx - related to Qiskit/qiskit#9346

Details and comments

[jyu00]

@kt474 can you also update the README? Like we did for ibmq-provider.

[coveralls]

Pull Request Test Coverage Report for Build 8713799347

Warning: This coverage report may be inaccurate.

This pull request's base commit is no longer the HEAD commit of its target branch. This means it includes changes from outside the original pull request, including, potentially, unrelated coverage changes.

• For more information on this, see Tracking coverage changes with pull request builds.
• To avoid this issue with future PRs, see these Recommended CI Configurations.
• For a quick fix, rebase this PR at GitHub. Your next report should be accurate.

Details

• 2 of 2 (100.0%) changed or added relevant lines in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.02%) to 43.392%

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Totals
Change from base Build 8253918978:	0.02%
Covered Lines:	2945
Relevant Lines:	6787

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💛 - Coveralls

[jyu00]

Can you also add (NOW DEPRECATED) to the first line of the README? Similar to what ibmq-provider has. The rest looks good.