Introduce harmonic balance and HB adjoint capabilities

Created by: msanchezmartinez

Context

The present PR updates the code to solve harmonic balance problems, including those with a priori unknown frequency. It also extends the code to handle harmonic balance adjoint problems.

Changes

• Implementation of harmonic balance capabilities

  • Currently working for SU2 (fluid only) and NativeSolid

• Implementation of adjoint harmonic balance capabilities

  • Currently working for SU2 (fluid only) and NativeSolid

• Fixed SU2Solid to work again

• Compatible with:

  • NativeSolid, v1.2 + HB
  • Metafor
  • modali, v2.0
  • SU2, v7.4.0 + HB
  • PFEM
  • PFEM3D
  • DART, v1.3.0 (interface to be updated in DART)
  • VLM, v2.0 (to be tested)
  • FPM, v1.0.1

Known issues

• Some solvers' interfaces have been modified but are yet to be tested. The codes do not work on my machine as of now
  • Since DART's interface is in a different repo, it has to be updated there as well (same changes as in FPM, with those it works for the modali and RBM test cases)
• Consistent adjoint and harmonic balance calculations are not included
• The HB adjoint test case takes too long
• Issue #3
• Issue #27 (the SU2+RBM unsteady results have changed again)