Add support for sorting joined tables

[kstefanou52]

Issue

Mongo driver didn't support to query results with sorting option for joined tables as describing here.

Enable sorting for joined tables

[Joannis]

I could've sworn I left a review already, but it seems I posted my feedback on Discord. Thanks for the ping @0xTim .

The main thing preventing approval is the missing some tests

[Joannis]

@gwynne is it doable to add these type of tests to FluentKit?

[codecov-commenter]

Codecov Report

Merging #53 (ec79b7e) into main (a4237b9) will increase coverage by 2.34%.
Report is 1 commits behind head on main.
The diff coverage is 95.65%.

❗ Current head ec79b7e differs from pull request most recent head 000a562. Consider uploading reports for the commit 000a562 to get more accurate results

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #53      +/-   ##
==========================================
+ Coverage   72.59%   74.93%   +2.34%     
==========================================
  Files          20       20              
  Lines         686      826     +140     
==========================================
+ Hits          498      619     +121     
- Misses        188      207      +19     

Files	Coverage Δ
...ources/FluentMongoDriver/DatabaseQuery+Mongo.swift	100.00% <100.00%> (+3.22%)	⬆️
Sources/FluentMongoDriver/MongoDB+Join.swift	69.60% <100.00%> (+14.13%)	⬆️
Sources/FluentMongoDriver/MongoDB+Read.swift	93.18% <100.00%> (+1.07%)	⬆️
Sources/FluentMongoDriver/Sort.swift	89.28% <93.75%> (+9.28%)	⬆️

... and 16 files with indirect coverage changes