refactor(generator): relocate FormatQueryParameterCode

[dbolduc]

Part of the work for #14510

This is a pure refactor. I will be getting rid of this visitor. To keep the diffs small, pull out the FormatQueryParameterCode function first.

Note that we:

• add method as a parameter
• return a std::string, instead of setting method_http_query_parameters in the function

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This change is 

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 93.59%. Comparing base (3fed367) to head (4465cf2).

Additional details and impacted files

@@           Coverage Diff           @@
##             main   #14513   +/-   ##
=======================================
  Coverage   93.59%   93.59%           
=======================================
  Files        2316     2316           
  Lines      207105   207100    -5     
=======================================
- Hits       193838   193835    -3     
+ Misses      13267    13265    -2     

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