feat: add * operator EXCEPT modifier

[recharte]

Adds the * operator EXCEPT modifier where one can specify the names of one or more columns to exclude from the result. All matching column names are omitted from the output.

[codecov[bot]]

Codecov Report

Merging #66 (cbecdda) into master (c379afa) will increase coverage by 0.06%. The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master      #66      +/-   ##
==========================================
+ Coverage   95.91%   95.97%   +0.06%     
==========================================
  Files          10       10              
  Lines        1076     1094      +18     
==========================================
+ Hits         1032     1050      +18     
  Misses         44       44              

Impacted Files	Coverage Δ
spyql/cli.py	99.00% <100.00%> (+0.02%)	:arrow_up:
spyql/processor.py	96.60% <100.00%> (+0.15%)	:arrow_up:

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