feat: add SQL Grader XBlock

[irtazaakram]

This PR moved Qualtrics Survey XBlock from https://github.com/openedx/xblock-sql-grader

• Resolves XBlock SQL Grader Migration #10
• Related to Consolidate Optional XBlocks public-engineering#317

The original repository is being deprecated here:

[codecov]

Codecov Report

❌ Patch coverage is 92.71255% with 18 lines in your changes missing coverage. Please review.
✅ Project coverage is 92.71%. Comparing base (3c4c8d1) to head (e4c187d).

Files with missing lines	Patch %	Lines
src/sql_grader/problem.py	90.47%	8 Missing and 2 partials ⚠️
src/sql_grader/xblocks.py	86.66%	4 Missing ⚠️
src/sql_grader/mixins/fragment.py	93.93%	1 Missing and 1 partial ⚠️
src/sql_grader/mixins/scenario.py	77.77%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #18      +/-   ##
==========================================
+ Coverage   83.33%   92.71%   +9.37%     
==========================================
  Files           1        7       +6     
  Lines           6      247     +241     
  Branches        1       21      +20     
==========================================
+ Hits            5      229     +224     
- Misses          0       15      +15     
- Partials        1        3       +2     

Flag	Coverage Δ
unittests	92.71% <92.71%> (+9.37%)	⬆️

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