Add a utility for calculating negotiations in a centralized way

[mxgrey]

This PR introduces a utility with a stable public API for easily calculating a traffic negotiation with the standard "AGV" planner in a centralized way. This PR also replaces the use of the "NegotiationRoom" utility that the tests were using. The tests now use the CentralizedNegotiation tool, whose implementation was largely derived from NegotiationRoom.

[codecov[bot]]

Codecov Report

Merging #66 (54f8fb2) into main (b8cee0d) will increase coverage by 0.03%. The diff coverage is 13.30%.

@@            Coverage Diff             @@
##             main      #66      +/-   ##
==========================================
+ Coverage   22.12%   22.15%   +0.03%     
==========================================
  Files         357      359       +2     
  Lines       29171    29175       +4     
  Branches    13330    13302      -28     
==========================================
+ Hits         6453     6464      +11     
- Misses      13767    13806      +39     
+ Partials     8951     8905      -46     

Flag	Coverage Δ
tests	22.15% <13.30%> (+0.03%)	:arrow_up:

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Impacted Files	Coverage Δ
...affic/include/rmf_traffic/agv/SimpleNegotiator.hpp	0.00% <ø> (ø)
...raffic/include/rmf_traffic/schedule/Negotiator.hpp	0.00% <ø> (ø)
...t/agv/planning/test_DifferentialDriveHeuristic.cpp	37.62% <ø> (ø)
rmf_traffic/test/unit/agv/test_Negotiator.cpp	10.82% <7.22%> (-1.94%)	:arrow_down:
...affic/test/unit/agv/test_Negotiation_edgecases.cpp	6.82% <8.33%> (+0.32%)	:arrow_up:
...fic/src/rmf_traffic/agv/CentralizedNegotiation.cpp	25.00% <25.00%> (ø)
...f_traffic/src/rmf_traffic/agv/SimpleNegotiator.cpp	34.97% <72.72%> (+7.79%)	:arrow_up:
...mf_traffic/src/rmf_traffic/schedule/Negotiator.cpp	60.71% <72.72%> (-4.29%)	:arrow_down:
...include/rmf_traffic/agv/CentralizedNegotiation.hpp	100.00% <100.00%> (ø)
... and 8 more