Add Pyomo.DOE to contrib

[jialuw96]

Fixes # .

Summary/Motivation: Contribute model-based design of experiments framework to Pyomo

Tasks to complete before merging:

• Merge PR on fork Add extra index to package jialuw96/pyomo#5
• Add documentation in sphinx
• Confirm tests work
• Add CCSI2 licence

Legal Acknowledgement

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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.

[blnicho]

I found lots of typos and have a few other minor suggestions but this is getting really close.

[jialuw96]

@blnicho This PR is ready for review. Thank you!

[blnicho]

@jialuw96 I'm still seeing errors in the ReadtheDocs build with some of the autoclass commands. This is the output:

WARNING: autodoc: failed to import class 'fim_doe.DesignOfExperiments' from module 'pyomo.contrib.doe'; the following exception was raised:
No module named 'pyomo.contrib.doe.fim_doe'
/home/docs/checkouts/readthedocs.org/user_builds/pyomo/checkouts/2294/pyomo/contrib/doe/measurements.py:docstring of pyomo.contrib.doe.measurements.Measurements.__init__:4: WARNING: Definition list ends without a blank line; unexpected unindent.
WARNING: autodoc: failed to import class 'FIM_result' from module 'pyomo.contrib.doe'; the following exception was raised:
Traceback (most recent call last):
  File "/home/docs/checkouts/readthedocs.org/user_builds/pyomo/envs/2294/lib/python3.7/site-packages/sphinx/util/inspect.py", line 376, in safe_getattr
    return getattr(obj, name, *defargs)
AttributeError: module 'pyomo.contrib.doe' has no attribute 'FIM_result'

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "/home/docs/checkouts/readthedocs.org/user_builds/pyomo/envs/2294/lib/python3.7/site-packages/sphinx/ext/autodoc/importer.py", line 98, in import_object
    obj = attrgetter(obj, mangled_name)
  File "/home/docs/checkouts/readthedocs.org/user_builds/pyomo/envs/2294/lib/python3.7/site-packages/sphinx/ext/autodoc/__init__.py", line 306, in get_attr
    return autodoc_attrgetter(self.env.app, obj, name, *defargs)
  File "/home/docs/checkouts/readthedocs.org/user_builds/pyomo/envs/2294/lib/python3.7/site-packages/sphinx/ext/autodoc/__init__.py", line 2804, in autodoc_attrgetter
    return safe_getattr(obj, name, *defargs)
  File "/home/docs/checkouts/readthedocs.org/user_builds/pyomo/envs/2294/lib/python3.7/site-packages/sphinx/util/inspect.py", line 392, in safe_getattr
    raise AttributeError(name) from exc
AttributeError: FIM_result

WARNING: autodoc: failed to import class 'Grid_Search_Result' from module 'pyomo.contrib.doe'; the following exception was raised:
Traceback (most recent call last):
  File "/home/docs/checkouts/readthedocs.org/user_builds/pyomo/envs/2294/lib/python3.7/site-packages/sphinx/util/inspect.py", line 376, in safe_getattr
    return getattr(obj, name, *defargs)
AttributeError: module 'pyomo.contrib.doe' has no attribute 'Grid_Search_Result'

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "/home/docs/checkouts/readthedocs.org/user_builds/pyomo/envs/2294/lib/python3.7/site-packages/sphinx/ext/autodoc/importer.py", line 98, in import_object
    obj = attrgetter(obj, mangled_name)
  File "/home/docs/checkouts/readthedocs.org/user_builds/pyomo/envs/2294/lib/python3.7/site-packages/sphinx/ext/autodoc/__init__.py", line 306, in get_attr
    return autodoc_attrgetter(self.env.app, obj, name, *defargs)
  File "/home/docs/checkouts/readthedocs.org/user_builds/pyomo/envs/2294/lib/python3.7/site-packages/sphinx/ext/autodoc/__init__.py", line 2804, in autodoc_attrgetter
    return safe_getattr(obj, name, *defargs)
  File "/home/docs/checkouts/readthedocs.org/user_builds/pyomo/envs/2294/lib/python3.7/site-packages/sphinx/util/inspect.py", line 392, in safe_getattr
    raise AttributeError(name) from exc
AttributeError: Grid_Search_Result

[adowling2]

Looking forward to further improves per #2610