SDK-2208 replace bnc field defines

[echo-branch]

Reference

SDK-2208 replace BNC field defines.

Summary

BNCFieldDefines.h was replaced with regular Objective-C code. Mostly equivalent code was added to a category.

Motivation

This is to unblock a fix for non-Xcode versions of SPM.

Type Of Change

• Bug fix (non-breaking change which fixes an issue)

Testing Instructions

Existing functionality and unit tests should work.

cc @BranchMetrics/saas-sdk-devs for visibility.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (bf6e9ee) 50.73% compared to head (f005401) 50.81%.
Report is 2 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1347      +/-   ##
==========================================
+ Coverage   50.73%   50.81%   +0.07%     
==========================================
  Files          68       67       -1     
  Lines       10081    10092      +11     
  Branches     3864     3789      -75     
==========================================
+ Hits         5115     5128      +13     
+ Misses       4708     4707       -1     
+ Partials      258      257       -1     

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[echo-branch]

I merged this into the PR for tuist as this is blocking cocoapods functionality. We only need to merge the other one, but this isolates the change for this.
#1349