feat: enable query caching by using GET instead of POST

[cbaker6]

New Pull Request Checklist

• [x] I am not disclosing a vulnerability.
• [x] I am creating this PR in reference to an issue.

Issue Description

All queries currently use POST requests, preventing the ability to leverage the cache policies available in the SDK.

Related issue: #382

Approach

Enable all queries to use GET requests by default so queries are cached. Developers can change the default request behavior for all queries by setting usingPostForQuery = true to not cache any of the queries. Setting usingPostForQuery = true can be useful when using the Swift SDK on the server-side as many developers will not want the server caching queries.

TODOs before merging

• [x] Add tests
• [x] Add entry to changelog
• [x] Add changes to documentation (guides, repository pages, in-code descriptions)

[parse-github-assistant[bot]]

Thanks for opening this pull request!

• 🎉 We are excited about your hands-on contribution!

[codecov[bot]]

Codecov Report

Merging #386 (7e0c992) into main (7ba4f95) will decrease coverage by 0.52%. The diff coverage is 80.99%.

@@            Coverage Diff             @@
##             main     #386      +/-   ##
==========================================
- Coverage   89.66%   89.13%   -0.53%     
==========================================
  Files         155      156       +1     
  Lines       14125    14528     +403     
==========================================
+ Hits        12665    12950     +285     
- Misses       1460     1578     +118     

Impacted Files	Coverage Δ
Sources/ParseSwift/API/API.swift	99.35% <ø> (-0.03%)	:arrow_down:
...urces/ParseSwift/API/API+NonParseBodyCommand.swift	81.09% <77.77%> (-0.44%)	:arrow_down:
Sources/ParseSwift/Types/Query.swift	87.47% <80.72%> (-7.67%)	:arrow_down:
Sources/ParseSwift/API/API+Command.swift	89.21% <100.00%> (ø)
Sources/ParseSwift/Extensions/Dictionary.swift	100.00% <100.00%> (ø)
Sources/ParseSwift/Parse.swift	98.79% <100.00%> (+0.02%)	:arrow_up:
Sources/ParseSwift/Objects/ParseObject.swift	84.80% <0.00%> (-0.31%)	:arrow_down:

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[cbaker6]

@aliasad106 you can try out this branch for query cache. It should work without any changes needed on your end as long as you didn't change the default cache policy of the SDK. I've tested it with some of the query code in Playgrounds and it seems to work.

I still need to add test cases to ensure this doesn't break in the future and to fix the code coverage.