Add cloning functionality to StateSpace

[jslee02]

This PR introduces clone functionality to StateSpace.

Usage:

SO2 so2;

auto s1 = so2.createState();
s1.setAngle(angle);
 
auto s2 = s1.clone(); // or auto s2 = so2.cloneState(s1);

This PR is part of #413 and depends on #419.

---

Before creating a pull request

• Document new methods and classes
• Format code with make format

Before merging a pull request

• Set version target by selecting a milestone on the right side
• Summarize this change in CHANGELOG.md
• Add unit test(s) for this change

[codecov]

Codecov Report

Merging #422 into master will increase coverage by 0.06%.
The diff coverage is 86.66%.

@@            Coverage Diff             @@
##           master     #422      +/-   ##
==========================================
+ Coverage   79.64%   79.71%   +0.06%     
==========================================
  Files         231      231              
  Lines        5960     5990      +30     
==========================================
+ Hits         4747     4775      +28     
- Misses       1213     1215       +2

Impacted Files	Coverage Δ
include/aikido/statespace/CartesianProduct.hpp	100% <ø> (ø)	⬆️
include/aikido/statespace/ScopedState.hpp	100% <ø> (ø)	⬆️
include/aikido/statespace/SO3.hpp	100% <ø> (ø)	⬆️
include/aikido/statespace/Rn.hpp	100% <ø> (ø)	⬆️
include/aikido/statespace/SO2.hpp	100% <ø> (ø)	⬆️
include/aikido/statespace/StateSpace.hpp	100% <ø> (ø)	⬆️
include/aikido/statespace/SE2.hpp	100% <ø> (ø)	⬆️
include/aikido/statespace/detail/SO3-impl.hpp	100% <ø> (ø)	⬆️
include/aikido/statespace/SE3.hpp	100% <ø> (ø)	⬆️
src/statespace/StateSpace.cpp	55.55% <0%> (-15.88%)	⬇️
... and 8 more