Alternative Solutions documentation add

[viens-code]

Fixes # .

Adds more documentation for contrib/alternative_solutions

Summary/Motivation:

Adds more documentation for contrib/alternative_solutions

Changes proposed in this PR:

• Provides paper citation for contrib/alternative_solutions/balas.py
• Adds optimality gap Knapsack examples to alternative_solutions documentation

Legal Acknowledgement

By contributing to this software project, I have read the contribution guide and agree to the following terms and conditions for my contribution:

1. I agree my contributions are submitted under the BSD license.
2. I represent I am authorized to make the contributions and grant the license. If my employer has rights to intellectual property that includes these contributions, I represent that I have received permission to make contributions and grant the required license on behalf of that employer.

[viens-code]

@mrmundt What needs to be done to get this past pending with Jenkins?

[mrmundt]

@viens-code the conflicts need to be resolved first

[viens-code]

Ah, ok.
Looks like Pyomo/pyomo:doc-reorg doesn't have contributed_packages in it yet in OnlineDocs
So what was supposed to be a couple tweaks to alternative_solutions is introducing all the old docs

[jsiirola]

AOS is still there. As part of the reorg it moved to explanation/analysis/alternative_solutions.rst

[jsiirola]

Overall this looks good. A couple minor formatting changes to suppress build warnings

[mrmundt]

@viens-code - Hello! We are planning to cut a patch release on Monday - do you think you will be able to look at this again before then?