Update NHS with coordinates array instead of coordinates function

[efaulhaber]

This may seem like a step back from #121, but now the NHS can be updated both by passing an array or by passing a coordinate function (for maximum flexibility of the NHS).
When we update and initialize the NHS from the semidiscretization, however, we use the more high-level coordinate array, which allows us to use different NHS implementations that work with coordinate arrays and not coordinate functions (for maximum flexibility of the semidiscretization).

This PR specifically prepares the NHS update to work with CellListMap.jl.

Depends on #68.

[codecov]

Codecov Report

Merging #127 (fdefc4b) into main (c5fc752) will decrease coverage by 0.02%.
The diff coverage is 22.58%.

@@            Coverage Diff             @@
##             main     #127      +/-   ##
==========================================
- Coverage   49.10%   49.08%   -0.02%     
==========================================
  Files          36       36              
  Lines        2185     2194       +9     
==========================================
+ Hits         1073     1077       +4     
- Misses       1112     1117       +5     

Flag	Coverage Δ
unitandintegration	49.08% <22.58%> (-0.02%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
examples/n_body/n_body_container.jl	0.00% <0.00%> (ø)
src/sph/neighborhood_search.jl	77.31% <0.00%> (-3.33%)	⬇️
src/semidiscretization/semidiscretization.jl	48.88% <10.52%> (ø)
test/unit/interactions/solid.jl	78.04% <50.00%> (-1.44%)	⬇️
src/containers/container.jl	72.22% <100.00%> (+1.63%)	⬆️
test/unit/containers/solid_container.jl	93.10% <100.00%> (+0.24%)	⬆️

[LasNikas]

Really nice! That makes a lot of things easier.