Add pratio and maxdim

[eliascarv]

This PR adds pratio option to EigenAnalysis and change ndim to maxdim.
I made some decisions to this implementation:

• Make pratio and maxdim kwargs to give the user option to choose one of these, both or neither.
• Change ndim to maxdim to make sense with pratio implementation.

closes #88

[juliohm]

Hi @eliascarv I can give a more detailed review after 17hs BRT today. I wonder if we should preserve the semantic of ndim and use ndim and pratio as mutually exclusive options. That is what I had in mind originally.

Let's chat over Zulip to align detail later today.

[codecov-commenter]

Codecov Report

Merging #89 (fed417c) into master (0db52f0) will increase coverage by 0.50%.
The diff coverage is 95.23%.

@@            Coverage Diff             @@
##           master      #89      +/-   ##
==========================================
+ Coverage   93.12%   93.62%   +0.50%     
==========================================
  Files          23       24       +1     
  Lines         567      596      +29     
==========================================
+ Hits          528      558      +30     
+ Misses         39       38       -1     

Impacted Files	Coverage Δ
src/transforms/eigenanalysis.jl	83.58% <95.23%> (+3.92%)	⬆️
src/transforms/sort.jl	100.00% <0.00%> (ø)

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[juliohm]

Review attached.

[juliohm]

Amazing PR as usual @eliascarv , super clean and professional coding 💯 Let's just wait for the tests to pass.