feat(#101) split hook methods in mixins to maximize atomicity and type safety

[francescovallone]

Description

Proposed mixins and methods that will expose:

OnRequestResponse: onRequest, onResponse;
OnBeforeHandle: beforeHandle (valid also for route);
OnAfterHandle: afterHandle (valid also for route);
OnTransform: transform (valid only for route);

We reduce the overhead of the request handler because it won't have to iterate through all the hooks but only through the hooks with that specific mixin.

Fixes #101

Type of change

Please delete options that are not relevant.

• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published in downstream modules

[codecov]

Codecov Report

Attention: Patch coverage is 95.04132% with 6 lines in your changes missing coverage. Please review.

Project coverage is 90.67%. Comparing base (290dea8) to head (6219282).
Report is 8 commits behind head on develop.

Files with missing lines	Patch %	Lines
packages/serinus/test/core/hook_test.dart	92.98%	4 Missing ⚠️
...ckages/serinus/lib/src/http/internal_response.dart	66.66%	2 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##           develop     #102      +/-   ##
===========================================
+ Coverage    90.30%   90.67%   +0.36%     
===========================================
  Files           77       79       +2     
  Lines         2910     2981      +71     
===========================================
+ Hits          2628     2703      +75     
+ Misses         282      278       -4     

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