Clean up the code

[romainljsimon]

Big PR:

• Change cell_list name to neighbour_list as it is more user friendly.
• Merge destroy_particle!,create_particle!and compute_local_energy into compute_energy_particle. This is possible thanks to deletion of the energy cache.
• We precalculate the cell neighbours, as we've seen that the calculation at each MC move of neighbours took too much time. We thus see an acceleration of the code.
• Compliance to the new version of code in the test files

[codecov]

Codecov Report

Attention: Patch coverage is 74.84663% with 41 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
src/neighbours.jl	75.47%	26 Missing ⚠️
src/atoms.jl	68.42%	6 Missing ⚠️
src/molecules.jl	68.75%	5 Missing ⚠️
src/ParticlesMC.jl	33.33%	2 Missing ⚠️
src/moves.jl	88.88%	2 Missing ⚠️

Files with missing lines	Coverage Δ
src/IO/IO.jl	80.42% <100.00%> (ø)
src/ParticlesMC.jl	71.42% <33.33%> (+15.87%)	⬆️
src/moves.jl	66.01% <88.88%> (+1.37%)	⬆️
src/molecules.jl	84.84% <68.75%> (+9.12%)	⬆️
src/atoms.jl	80.32% <68.42%> (+8.78%)	⬆️
src/neighbours.jl	75.47% <75.47%> (ø)

... and 1 file with indirect coverage changes

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.