Split util namespace into common and io namespaces

[jslee02]

addresses #181

[brianhou]

Can you add a PR to libherb that uses the updated namespaces? Thanks!

[jslee02]

Can you add a PR to libherb that uses the updated namespaces?

👍 personalrobotics/libherb#48

[codecov]

Codecov Report

Merging #225 into master will not change coverage.
The diff coverage is 87.5%.

@@           Coverage Diff           @@
##           master     #225   +/-   ##
=======================================
  Coverage   70.83%   70.83%           
=======================================
  Files         172      172           
  Lines        5033     5033           
  Branches      800      800           
=======================================
  Hits         3565     3565           
  Misses        980      980           
  Partials      488      488

Impacted Files	Coverage Δ
...ude/aikido/constraint/uniform/SE2BoxConstraint.hpp	100% <ø> (ø)	⬆️
.../constraint/detail/JointStateSpaceHelpers-impl.hpp	48.67% <ø> (ø)	⬆️
include/aikido/constraint/TSR.hpp	100% <ø> (ø)	⬆️
src/distance/defaults.cpp	100% <ø> (ø)	⬆️
...lude/aikido/constraint/uniform/RnBoxConstraint.hpp	100% <ø> (ø)	⬆️
...constraint/uniform/detail/RnBoxConstraint-impl.hpp	69.07% <ø> (ø)	⬆️
src/constraint/uniform/SE2BoxConstraint.cpp	73.07% <ø> (ø)	⬆️
include/aikido/statespace/StateSpace.hpp	100% <ø> (ø)	⬆️
...de/aikido/constraint/uniform/SO2UniformSampler.hpp	100% <ø> (ø)	⬆️
src/planner/parabolic/ParabolicSmoother.cpp	100% <ø> (ø)	⬆️
... and 20 more