Remove for loop from getFieldPathForName

[Ektaros]

This PR removes for loops from getFieldPathForName by introducing new map to serializer which helps to find fields by their name.
This results in ~25% faster parsing. Here are numbers from my machine for current master:
File size: 81 MB
Elapsed: 3.665982666s
File size: 107 MB
Elapsed: 4.7228615s
File size: 159 MB
Elapsed: 10.646743625s

And here is this branch results:
File size: 81 MB
Elapsed: 2.72868975s
File size: 107 MB
Elapsed: 3.623294709s
File size: 159 MB
Elapsed: 7.519242125s

[markus-wa]

very nice! great stuff @Ektaros 🥳

[codecov]

Codecov Report

All modified lines are covered by tests ✅

Comparison is base (b70c827) 80.11% compared to head (9e0d8e4) 80.17%.

❗ Current head 9e0d8e4 differs from pull request most recent head b8a4f97. Consider uploading reports for the commit b8a4f97 to get more accurate results

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #428      +/-   ##
==========================================
+ Coverage   80.11%   80.17%   +0.05%     
==========================================
  Files          47       47              
  Lines        6165     6168       +3     
==========================================
+ Hits         4939     4945       +6     
+ Misses       1017     1016       -1     
+ Partials      209      207       -2     

Files	Coverage Δ
pkg/demoinfocs/sendtables2/parser.go	84.33% <100.00%> (ø)
pkg/demoinfocs/sendtables2/serializer.go	59.52% <100.00%> (+14.36%)	⬆️

... and 3 files with indirect coverage changes

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