Introduce Path type intended for storing nested path in type level

[MateuszKubuszok]

This task intends to change the type level representation of paths used for fields overrides. It is necessary to enable future work on #358 without breaking binary compatibility (source compatibility would be preserved but someone linking to code compiled with older version might have issues, so it would force version bump to 0.9.0).

This task does NOT intend to implement #358 as 0.8.0 is intended to avoid additional features.

TODO:

• create internal.runtime.Path type
• create its representation in ChimneyTypes
• change TransformerCfg to use Path instead of String
• change DSL macros to return Select["fieldName", Root] instead of String
  • at this point nested path will still be rejected by DSL
• change config parser to parse Select["fieldName", Root] to "fieldName"
  • at this point config parsing would also reject nested paths if anyone attempted them

[codecov]

Codecov Report

Patch coverage: 82.25% and project coverage change: -0.25% ⚠️

Comparison is base (d53f562) 80.18% compared to head (6d2db18) 79.93%.

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #377      +/-   ##
==========================================
- Coverage   80.18%   79.93%   -0.25%     
==========================================
  Files         109      109              
  Lines        4133     4192      +59     
  Branches      173      193      +20     
==========================================
+ Hits         3314     3351      +37     
- Misses        819      841      +22     

Files Changed	Coverage Δ
...etime/dsl/PartialTransformerDefinitionMacros.scala	83.78% <0.00%> (ø)
...etime/dsl/PartialTransformerDefinitionMacros.scala	83.78% <ø> (ø)
...compiletime/dsl/PartialTransformerIntoMacros.scala	100.00% <ø> (ø)
.../compiletime/dsl/TransformerDefinitionMacros.scala	63.63% <ø> (ø)
...ternal/compiletime/dsl/TransformerIntoMacros.scala	100.00% <ø> (ø)
...nd/chimney/internal/compiletime/ChimneyTypes.scala	100.00% <ø> (+6.66%)	⬆️
...letime/derivation/transformer/Configurations.scala	77.38% <75.00%> (-0.12%)	⬇️
...ey/internal/compiletime/ChimneyTypesPlatform.scala	70.58% <85.00%> (-0.38%)	⬇️
...ey/internal/compiletime/ChimneyTypesPlatform.scala	82.11% <93.33%> (-3.10%)	⬇️
...compiletime/dsl/PartialTransformerIntoMacros.scala	100.00% <100.00%> (ø)
... and 2 more

... and 8 files with indirect coverage changes

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.