feat(c3) Additional cost calculation functions used by sampling C3 examples

[ebianchi]

Most of the cost calculation functionality used by sampling C3 examples (not in the C3 repo) was introduced by the merged PR #44. This PR brings a few minor additional features that are useful for the downstream use cases:

1. Quadratic trajectory costs can be computed for a subset of data vector indices. Bindings and tests are included for these new input argument options for ComputeQuadraticTrajectoryCost.
2. LCS-based PD control can be simulated with or without feedforward control terms, which can be switched on or off via a boolean argument. Bindings and tests are included for these new input argument options for SimulatePDControlWithLCS.
3. LCS-based PD control now takes in an LCS simulation configuration object (LCSSimulateConfig type). This should have been included earlier.

Confirmed that all tests (old and new) run successfully after introduction of these changes.

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This change is 

[github-actions]

LCOV of commit d95bdf8 during C3 Coverage #146

Summary coverage rate:
  lines......: 92.3% (2109 of 2284 lines)
  functions..: 81.4% (206 of 253 functions)
  branches...: 49.1% (1725 of 3516 branches)

Files changed coverage rate:
                                                          |Lines       |Functions  |Branches    
  Filename                                                |Rate     Num|Rate    Num|Rate     Num
  ==============================================================================================
  core/traj_eval.cc                                       |14.1%     99|1300%    12|    -      0
  core/traj_eval.h                                        |44.4%     63| 314%    28|    -      0

[Meow404]

@Meow404 reviewed 5 files and all commit messages.
Reviewable status: complete! all files reviewed, all discussions resolved (waiting on ebianchi).