refactor(dynamite): split JsonSchema into separate library

[Leptopoda]

This reorganizes the Schema handling by splitting of the validators and general schema handling.
Schemas are now split per types where only the relvant attributes are taken into account.

This will allow easier integration of #1247 and broader cleanups by only passing a specific schema type arround.

[codecov]

Codecov Report

Attention: Patch coverage is 75.71429% with 51 lines in your changes are missing coverage. Please review.

Project coverage is 28.72%. Comparing base (b3124a5) to head (5626064).
Report is 5 commits behind head on main.

❗ Current head 5626064 differs from pull request most recent head ffa5b32. Consider uploading reports for the commit ffa5b32 to get more accurate results

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1931      +/-   ##
==========================================
+ Coverage   28.53%   28.72%   +0.18%     
==========================================
  Files         246      247       +1     
  Lines       81761    83379    +1618     
==========================================
+ Hits        23331    23951     +620     
- Misses      58430    59428     +998     

Flag	Coverage Δ		*Carryforward flag
dynamite	30.51% <75.71%> (+7.94%)	⬆️
dynamite_end_to_end_test	62.63% <ø> (+0.46%)	⬆️
dynamite_runtime	82.65% <ø> (ø)		Carriedforward from 729e5ae
neon_dashboard	92.56% <ø> (ø)
neon_framework	38.36% <ø> (ø)
neon_talk	96.67% <ø> (ø)
nextcloud	25.69% <ø> (+<0.01%)	⬆️
sort_box	90.90% <ø> (ø)		Carriedforward from 729e5ae

*This pull request uses carry forward flags. Click here to find out more.

Files	Coverage Δ
.../dynamite/dynamite/lib/src/models/json_schema.dart	100.00% <100.00%> (ø)
.../dynamite/lib/src/models/json_schema/schema.g.dart	40.40% <ø> (ø)
...ages/dynamite/dynamite/lib/src/models/openapi.dart	100.00% <100.00%> (ø)
...te/dynamite/lib/src/models/openapi/components.dart	100.00% <ø> (ø)
...namite/dynamite/lib/src/models/openapi/header.dart	25.00% <ø> (ø)
...te/dynamite/lib/src/models/openapi/media_type.dart	50.00% <ø> (ø)
...ynamite/dynamite/lib/src/models/json_schema.g.dart	98.00% <98.00%> (ø)
...es/dynamite/dynamite/lib/src/models/openapi.g.dart	78.43% <0.00%> (-3.24%)	⬇️
.../dynamite/lib/src/models/openapi/components.g.dart	40.32% <50.00%> (ø)
...ite/dynamite/lib/src/models/openapi/parameter.dart	5.31% <0.00%> (-0.06%)	⬇️
... and 4 more

... and 28 files with indirect coverage changes

[provokateurin]

The second commit should also rename SchemaType to JsonSchemaType. Everything else LGTM