➖ Remove unit library due to increasing simulation runtimes.

[Drewniok]

Description

This PR reverses the use of the unit library. This is necessary because the runtimes of the physical simulation algorithms increase when the unit library is used.

Checklist:

• The pull request only contains commits that are related to it.
• I have added appropriate tests and documentation.
• I have made sure that all CI jobs on GitHub pass.
• The pull request introduces no new warnings and follows the project's style guidelines.

[marcelwa]

Many thanks for the effort. I don't see any immediate problems with it. There are just a couple more places where I would like to see unit hints in the docstrings.

[codecov]

Codecov Report

Merging #258 (2f8650a) into main (92bb036) will increase coverage by 0.10%.
The diff coverage is 99.07%.

@@            Coverage Diff             @@
##             main     #258      +/-   ##
==========================================
+ Coverage   94.57%   94.67%   +0.10%     
==========================================
  Files          85       84       -1     
  Lines        7669     7648      -21     
==========================================
- Hits         7253     7241      -12     
+ Misses        416      407       -9     

Files Changed	Coverage Δ
...imulation/sidb/calculate_energy_and_state_type.hpp	100.00% <ø> (ø)
...fiction/technology/charge_distribution_surface.hpp	99.61% <97.95%> (+4.06%)	⬆️
...clude/fiction/algorithms/path_finding/distance.hpp	100.00% <100.00%> (ø)
...lgorithms/simulation/sidb/critical_temperature.hpp	89.47% <100.00%> (ø)
...algorithms/simulation/sidb/energy_distribution.hpp	100.00% <100.00%> (ø)
...ion/algorithms/simulation/sidb/is_ground_state.hpp	100.00% <100.00%> (ø)
...tion/algorithms/simulation/sidb/minimum_energy.hpp	100.00% <100.00%> (ø)
.../sidb/occupation_probability_of_excited_states.hpp	96.87% <100.00%> (ø)
...hms/simulation/sidb/sidb_simulation_parameters.hpp	100.00% <100.00%> (+23.52%)	⬆️
...on/algorithms/simulation/sidb/time_to_solution.hpp	96.77% <100.00%> (ø)
... and 6 more

... and 1 file with indirect coverage changes