feat, refactor: Query Collections, read_query, electric slide

[Fyko]

This PR:

• breaks scyllax-macros into two libs, adding scyllax-macros-core
• refactors select_query into read_query
• refactors SelectQuery to ReadQuery
• starts using scyllax-parser in macros
• refactors delete_query into write_query
• refactors UpsertQuery to use write_query logic under the hood
• ejects the CachingSession, using property-accessing Query Collections (which is much faster)
• refactors Executor to use Query Collections
• bans placeholder variables, requiring named variables (? -> :id)
• creates the underlying structure for request coalescing

Closes #6

[codecov]

Codecov Report

Merging #13 (2582f66) into main (4a6c1c0) will decrease coverage by 0.21%.
The diff coverage is 68.97%.

@@            Coverage Diff             @@
##             main      #13      +/-   ##
==========================================
- Coverage   87.78%   87.57%   -0.21%     
==========================================
  Files          20       23       +3     
  Lines        1473     1618     +145     
==========================================
+ Hits         1293     1417     +124     
- Misses        180      201      +21     

Files	Coverage Δ
example/src/entities/person/model.rs	88.73% <100.00%> (+0.16%)	⬆️
example/src/entities/person_login/model.rs	92.15% <100.00%> (+0.15%)	⬆️
scyllax-macros-core/src/queries/mod.rs	100.00% <100.00%> (ø)
scyllax-macros/src/lib.rs	100.00% <100.00%> (+12.90%)	⬆️
scyllax-parser/src/select.rs	100.00% <100.00%> (ø)
scyllax/src/error.rs	100.00% <ø> (ø)
scyllax/src/maybe_unset.rs	100.00% <ø> (ø)
scyllax/src/util.rs	83.33% <ø> (ø)
scyllax-macros-core/src/enum.rs	90.90% <66.66%> (ø)
scyllax-macros-core/src/json.rs	97.61% <66.66%> (ø)
... and 9 more

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