feat: Add torch-based CMA-ES implementation

[NaturalGradient]

This pull request:

• Refactors the existing evotorch.algorithms.cmaes.CMAES, which is simply a wrapper for pycma to evotorch.algorithms.pycmaes.PyCMAES.
• Introduces a new, torch-based, implementation of CMAES under the name evotorch.algorithms.cmaes.CMAES. This aims to faithfully reimplement the most recent version of pycma, while also benefiting from the evotorch ecosystem e.g. vectorized, GPU based, working with torch tensors for compatibility with other features.
• Introduces evotorch.algorithms.restarters, which provides basic functionality for meta-algorithms that wrap around a SearchAlgorithm class + parameterization, and allow automatic restarting of the algorithm. This creates basic functionality for the eventual re-implementation e.g. of IPOP-CMA-ES and BIPOP-CMA-ES, and equivalent algorithms for XNES, SNES etc.
• Adds the is_terminated flag to all SearchAlgorithm classes, that will allow the user to define their own general functionality for detecting termination states that should trigger restarts. Currently, this value defaults to False, but in the future it is intended to add example termination states to the new CMAES implementation.

[codecov-commenter]

Codecov Report

Merging #41 (f8d776f) into master (d3e3f0a) will increase coverage by 24.02%. The diff coverage is 49.83%.

@@             Coverage Diff             @@
##           master      #41       +/-   ##
===========================================
+ Coverage   52.97%   77.00%   +24.02%     
===========================================
  Files          43       47        +4     
  Lines        6233     6532      +299     
===========================================
+ Hits         3302     5030     +1728     
+ Misses       2931     1502     -1429     

Impacted Files	Coverage Δ
src/evotorch/algorithms/restarter/__init__.py	0.00% <0.00%> (ø)
...rc/evotorch/algorithms/restarter/modify_restart.py	0.00% <0.00%> (ø)
src/evotorch/algorithms/restarter/restart.py	0.00% <0.00%> (ø)
src/evotorch/algorithms/pycmaes.py	21.83% <21.83%> (ø)
src/evotorch/algorithms/searchalgorithm.py	86.38% <66.66%> (+47.55%)	:arrow_up:
src/evotorch/algorithms/cmaes.py	83.92% <82.66%> (+62.58%)	:arrow_up:
src/evotorch/algorithms/__init__.py	100.00% <100.00%> (ø)
src/evotorch/decorators.py	100.00% <0.00%> (ø)
src/evotorch/tools/__init__.py	100.00% <0.00%> (ø)
src/evotorch/neuroevolution/net/__init__.py	100.00% <0.00%> (ø)
... and 26 more

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