Implement accurate intersection and union behavior for and/or queries

Created by: rvantonder

We need to evaluate and vs. or queries quite differently due to the semantics. This function splits up the logic in evaluateOperator to evaluateAnd and evaluateOr.

The task for getting an accurate number of results for something like count:100 in an and-query is quite complex. Please see in line comments.

I'm still testing this manually. Putting this up for review now because I've converged on the implementation.

Created by: codecov[bot]

Codecov Report

Merging #9815 into master will decrease coverage by 0.03%. The diff coverage is 0.00%.

@@            Coverage Diff             @@
##           master    #9815      +/-   ##
==========================================
- Coverage   42.68%   42.64%   -0.04%     
==========================================
  Files        1340     1340              
  Lines       73605    73659      +54     
  Branches     6629     6629              
==========================================
- Hits        31417    31413       -4     
- Misses      39348    39406      +58     
  Partials     2840     2840              

Flag	Coverage Δ
#unit	42.64% <0.00%> (-0.04%)

Impacted Files	Coverage Δ
cmd/frontend/graphqlbackend/search_alert.go	17.75% <0.00%> (-0.24%)
cmd/frontend/graphqlbackend/search_results.go	43.37% <0.00%> (-2.98%)
internal/search/query/types.go	35.41% <ø> (+0.55%)

Created by: rvantonder

Am merging now--this will get tests in e2e form or another. This functionality is still feature flagged (the flag is not advertised yet). I'll have more confidence about advertising the flag when doing testing and writing more tests after branch cut.