Implemented multi-section surface parameterization

[sabakhshi]

Purpose

In support of the Army/CDI project I have implemented a multi-section geometry group for OpenAeroStruct that allows the optimizer to have full control over individual wing sections using all existing OpenAeroStruct transformations. Two approaches for facilitating C0 continuity between sections, by constraint or by construction, are provided. In addition, an automatic mesh generator for multi-section wing is implemented. This feature can be back-ported to single-section surfaces in a future PR.

Expected time until merged

3 weeks

Type of change

• Bugfix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (non-backwards-compatible fix or feature)
• Code style update (formatting, renaming)
• Refactoring (no functional changes, no API changes)
• Documentation update
• Maintenance update
• Other (please describe)

Testing

Tests for multi-section geometries have been added.

Checklist

• I have run flake8 and black to make sure the Python code adheres to PEP-8 and is consistently formatted
• I have formatted the Fortran code with fprettify or C/C++ code with clang-format as applicable
• I have run unit and regression tests which pass locally with my changes
• I have added new tests that prove my fix is effective or that my feature works
• I have added necessary documentation

[sabakhshi]

Ready for review

[sabakhshi]

Ready for review