Stark problem and heyoka taylor integrators

[darioizzo]

The stark problem and the heyoka integrators are starting in this PR to be integrated into kep3.

In the old pykep propagate_taylor was a function and the Taylor integrator handwritten. In kep3 we use the heyoka dependency to interface to all Taylor propagation. This requires the use of a global cache as to avoid compiling all the time Taylor integrators. Hence the propagation is now done in a class called stark_problem.

Upon construction the Taylor integrator is taken from a cache and copied. Then used in all calls to the propagate functions.

[codecov]

Codecov Report

Attention: Patch coverage is 99.44751% with 1 line in your changes missing coverage. Please review.

Project coverage is 98.01%. Comparing base (616e097) to head (a48b3ad).
Report is 8 commits behind head on main.

Files with missing lines	Patch %	Lines
src/stark_problem.cpp	98.55%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #36      +/-   ##
==========================================
+ Coverage   97.92%   98.01%   +0.08%     
==========================================
  Files          25       28       +3     
  Lines        1641     1765     +124     
==========================================
+ Hits         1607     1730     +123     
- Misses         34       35       +1     

Files with missing lines	Coverage Δ
include/kep3/lambert_problem.hpp	100.00% <ø> (ø)
include/kep3/stark_problem.hpp	100.00% <100.00%> (ø)
src/core_astro/propagate_lagrangian.cpp	97.69% <100.00%> (+0.01%)	⬆️
src/epoch.cpp	85.71% <100.00%> (ø)
src/lambert_problem.cpp	100.00% <100.00%> (ø)
src/planet.cpp	100.00% <100.00%> (ø)
src/ta/lt_kepler.cpp	100.00% <100.00%> (ø)
src/stark_problem.cpp	98.55% <98.55%> (ø)