Add support for invokable class name & request handler

[rustamwin]

Q	A
Is bugfix?	✔️/❌
New feature?	✔️/❌
Breaks BC?	❌
Fixed issues	#85

[codecov]

Codecov Report

Patch coverage: 100.00% and no project coverage change.

Comparison is base (5609007) 100.00% compared to head (9b389a0) 100.00%.

❗ Current head 9b389a0 differs from pull request most recent head 78b9c0f. Consider uploading reports for the commit 78b9c0f to get more accurate results

Additional details and impacted files

@@             Coverage Diff             @@
##              master       #89   +/-   ##
===========================================
  Coverage     100.00%   100.00%           
- Complexity        85        91    +6     
===========================================
  Files              7         7           
  Lines            230       239    +9     
===========================================
+ Hits             230       239    +9     

Files Changed	Coverage Δ
src/MiddlewareFactory.php	100.00% <100.00%> (ø)

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[what-the-diff]

PR Summary

• Extend Capability of MiddlewareFactory Class
  The update enables the MiddlewareFactory to handle and support PSR-15 request handler classes and also invokable classes.

• Addition of InvokeableAction and SimpleRequestHandler classes
  Two new classes, InvokeableAction and SimpleRequestHandler, have been implemented to facilitate handling of invokable middleware and request handlers.

• Enhancement of Test Coverage
  To ensure everything is working as expected, extra testing cases have been integrated into the MiddlewareDispatcherTest and MiddlewareFactoryTest classes.

• Support for Simple Request Handler Implementation
  The introduction of SimpleRequestHandler allows straightforward execution and handling of requests.