SNOW-1416000 Structure types array null handling

[sfc-gh-astachowski]

Description

SNOW-1416000 Added new context option that makes values within arrays be parsed to sql.NullXYZ types, allowing for handling nulls in the data.

Checklist

• Created tests which fail without the change (if possible)
• Extended the README / documentation, if necessary

[codecov]

Codecov Report

Attention: Patch coverage is 53.47826% with 107 lines in your changes missing coverage. Please review.

Project coverage is 82.59%. Comparing base (cecf890) to head (c521e6a).
Report is 1 commits behind head on master.

Files	Patch %	Lines
converter.go	54.02%	97 Missing ⚠️
errors.go	0.00%	10 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1179      +/-   ##
==========================================
- Coverage   83.01%   82.59%   -0.43%     
==========================================
  Files          54       54              
  Lines       12658    12815     +157     
==========================================
+ Hits        10508    10584      +76     
- Misses       2150     2231      +81     

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[github-actions]

All contributors have signed the CLA ✍️ ✅
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[sfc-gh-astachowski]

I have read the CLA Document and I hereby sign the CLA