feat(core): add c3 plus

[Meow404]

This change is 

[github-actions]

LCOV of commit 24c419a during C3 Coverage #35

Summary coverage rate:
  lines......: 90.2% (1310 of 1453 lines)
  functions..: 75.8% (122 of 161 functions)
  branches...: 51.3% (1064 of 2074 branches)

Files changed coverage rate:
                                        |Lines       |Functions  |Branches    
  Filename                              |Rate     Num|Rate    Num|Rate     Num
  ============================================================================
  core/c3.cc                            | 7.5%    279|2350%    20|    -      0
  core/c3.h                             |14.3%     21|2100%     2|    -      0
  core/c3_miqp.cc                       | 2.7%     73|    #     2|    -      0
  core/c3_options.h                     | 1.6%     61|4400%     1|    -      0
  core/c3_plus.cc                       | 9.8%     51|2350%     4|    -      0
  core/c3_plus.h                        | 200%      1| 0.0%     2|    -      0
  core/c3_qp.cc                         | 6.1%     33|4300%     2|    -      0
  core/lcs.cc                           |14.0%     50|1100%     6|    -      0
  core/lcs.h                            |18.8%     16|2133%     3|    -      0
  core/test/c3_cartpole_problem.hpp     | 2.8%     72|5300%     2|    -      0
  multibody/geom_geom_collider.cc       |16.9%     65| 600%    10|    -      0
  multibody/lcs_factory.cc              | 4.9%    266|2862%    13|    -      0
  multibody/lcs_factory.h               |33.3%      3|1200%     1|    -      0
  systems/c3_controller.cc              | 4.7%    106|3040%     5|    -      0
  systems/c3_controller_options.h       |14.3%     14|2400%     1|    -      0
  systems/framework/c3_output.h         |36.4%     11| 667%     3|    -      0