Fill in first version of doc pages

[sea-bass]

This PR does a few things to get the docs ready for a first release.

• Adds "manually written" docs pages on the design philosophy and supported motion planning components.
• Cleans up the docs organization and autogenerated API docs.
• Adds docs generation to run automatically with pre-commit. which is super convenient.

[github-actions[bot]]

Coverage Report

File	Stmts	Miss	Cover	Missing
pyroboplan
__init__.py	0	0	100%
pyroboplan/core
__init__.py	0	0	100%
planning_context.py	8	8	0%	1, 4, 9, 13–15, 17–18
utils.py	85	2	97%	155–156
pyroboplan/ik
__init__.py	0	0	100%
differential_ik.py	87	14	83%	146–147, 156–157, 181, 187, 193, 196, 224, 227, 235–236, 241, 247
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	41	0	100%
utils.py	4	0	100%
pyroboplan/planning
__init__.py	0	0	100%
cartesian_planner.py	92	5	94%	115, 139, 143–144, 207
graph.py	40	0	100%
rrt.py	158	25	84%	129–130, 132–133, 149, 152, 160, 333, 378–383, 387–388, 392–394, 397–398, 406–407, 410–411
utils.py	6	0	100%
pyroboplan/trajectory
__init__.py	0	0	100%
polynomial.py	126	18	85%	127, 129–130, 132–134, 136–137, 140–143, 146, 151, 156, 165, 192, 261
trapezoidal_velocity.py	153	18	88%	283–284, 316, 318–322, 324–325, 328–331, 334, 339, 344, 353
pyroboplan/visualization
__init__.py	0	0	100%
meshcat_utils.py	18	11	38%	40–41, 43, 45, 57, 81–82, 109–111, 113
TOTAL	834	117	85%

Tests	Skipped	Failures	Errors	Time
62	0 :zzz:	0 :x:	0 :fire:	17.601s :stopwatch: