Support for SubDyn Floating Platforms and Rectangular Members

[yqliaohk]

NOT ready for review yet.

This PR will follow #420.

This PR collects a lot of the open-source developments required for the EAB case studies, including:

• Modeling rectangular members in HydroDyn and SubDyn
• A new hybrid potential_model_override method using potential model for only radiation and excitation (not bouyancy)
• New load cases (force-displacement, free decay, user-defined wind)
• Improved DLC 1.2 support, using probability clusters

Things left TODO:

• Elevate potential_model_override option above RAFT as it affects both RAFT and OpenFAST
• Add various flavors of VolturnUS modeling (rectangular, SubDyn, hybrid)
• Add fatigue example
• Organize pre-processing notebooks (fatigue, orcaflex translator)
• Test all new DLC cases
• Fix SubDyn generation, ElastoDyn mass needs to be zeroed
• Check heave of models

Purpose

This PR updates WEIS to generate HydroDyn and SubDyn files for rectangular members. The SubDyn update also applies to circular members.

Type of change

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Select the appropriate type(s) that describe this PR

• New feature (non-breaking change which adds functionality)

Testing

Explain the steps needed to test the new code to verify that it does indeed address the issue and produce the expected behavior.

Checklist

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• I have run existing tests which pass locally with my changes
• I have added new tests or examples that prove my fix is effective or that my feature works
• I have added necessary documentation

[coveralls]

coverage: 0.0% (-58.1%) from 58.139%
when pulling 8679f53 on yqliaohk:rectangular_update
into 9913da4 on WISDEM:develop.

[dzalkind]

Closing this PR to finish up on #447