Port key value parser from Stanza

[jsirianni]

Resolves #455

[codecov]

Codecov Report

Merging #459 (c182e23) into main (f9887c7) will increase coverage by 1.3%.
The diff coverage is 100.0%.

@@           Coverage Diff           @@
##            main    #459     +/-   ##
=======================================
+ Coverage   75.4%   76.7%   +1.3%     
=======================================
  Files         83      84      +1     
  Lines       3888    4111    +223     
=======================================
+ Hits        2933    3155    +222     
+ Misses       673     671      -2     
- Partials     282     285      +3     

Impacted Files	Coverage Δ
operator/parser/keyvalue/keyvalue.go	100.0% <100.0%> (ø)
entry/resource_field.go	97.6% <0.0%> (-2.4%)	⬇️
entry/attribute_field.go	97.6% <0.0%> (-2.4%)	⬇️
operator/input/tcp/tcp.go	78.4% <0.0%> (-1.6%)	⬇️
entry/body_field.go	100.0% <0.0%> (ø)
operator/transformer/recombine/recombine.go	77.7% <0.0%> (+2.0%)	⬆️
entry/field.go	98.1% <0.0%> (+2.9%)	⬆️
operator/helper/severity_builder.go	90.3% <0.0%> (+4.6%)	⬆️

[djaglowski]

Looks good. Just a couple nits.

[jsirianni]

@djaglowski thanks for the review, everything should be sorted out.