diesel: Replace all_columns with as_select()

[Turbo87]

With all_columns the field order inside the structs is very important and it is impossible to skip columns. as_select() solves both of these issues.

[codecov]

Codecov Report

Attention: Patch coverage is 96.29630% with 1 line in your changes missing coverage. Please review.

Project coverage is 88.79%. Comparing base (3de6c20) to head (1838132).
Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
src/admin/render_readmes.rs	0.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #9768      +/-   ##
==========================================
- Coverage   88.80%   88.79%   -0.01%     
==========================================
  Files         289      289              
  Lines       29816    29809       -7     
==========================================
- Hits        26479    26470       -9     
- Misses       3337     3339       +2     

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