Add polynomial trajectory generation

[sea-bass]

This PR adds cubic and quintic polynomial trajectory generation.

[github-actions]

Coverage Report

File	Stmts	Miss	Cover	Missing
pyroboplan
__init__.py	0	0	100%
pyroboplan/core
__init__.py	0	0	100%
planning_scene.py	5	5	0%	1, 3, 7–9
utils.py	52	8	84%	148–153, 155–156
pyroboplan/ik
__init__.py	0	0	100%
differential_ik.py	92	16	82%	127–128, 137–138, 162, 166–168, 174, 177, 205, 208, 216–217, 222, 228
nullspace_components.py	16	16	0%	3, 6, 22, 25, 45–46, 48–54, 57, 75–76
pyroboplan/models
__init__.py	0	0	100%
panda.py	40	0	100%
utils.py	4	0	100%
pyroboplan/planning
__init__.py	0	0	100%
graph.py	40	0	100%
rrt.py	165	25	84%	116–117, 119–120, 136–137, 145, 305, 350–355, 359–360, 364–366, 369–370, 378–379, 382–383
utils.py	6	0	100%
pyroboplan/trajectory
__init__.py	0	0	100%
polynomial.py	123	15	87%	124, 126–127, 129–130, 133–136, 139, 144, 149, 158, 185, 254
trapezoidal_velocity.py	146	13	91%	311, 313–315, 317, 320–323, 326, 331, 336, 345
pyroboplan/visualization
__init__.py	0	0	100%
meshcat_utils.py	18	11	38%	40–41, 43, 45, 57, 81–82, 109–111, 113
TOTAL	707	109	84%

Tests	Skipped	Failures	Errors	Time
50	0 💤	0 ❌	0 🔥	13.124s ⏱️