Enhance edge and vertex weights for HyPar optimizer

[jofrevalles]

Summary

This PR enhances the HyPar optimizer by adding two functions on its configuration that compute the weights for both edges and vertices. The functions edge_weight_scaling and vertex_weight_scaling enable the user to choose whether to apply a log, linear, exp, ... scaling into the size of the index (for the edges) or the product of the sizes of all the present indexes (for the vertices).

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (50e208a) 78.70% compared to head (694b3b2) 78.06%.
Report is 10 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master      #43      +/-   ##
==========================================
- Coverage   78.70%   78.06%   -0.64%     
==========================================
  Files          11       11              
  Lines         277      269       -8     
==========================================
- Hits          218      210       -8     
  Misses         59       59              

Files	Coverage Δ
src/EinExpr.jl	64.21% <100.00%> (-1.79%)	⬇️
src/Optimizers/KaHyPar.jl	100.00% <100.00%> (ø)

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[jofrevalles]

I think this could be already merged.