refactor(project): go-style v2 to pythonic v3

[cdddg]

In April 2023, I released version v2 of the project. Reflecting upon it, I recognized a strong influence of Go-specific styles in its structure. With this PR, I aim to refine the project's architecture, transitioning from the Go-centric design to one that aligns more closely with conventional Python practices.

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Changelog:

• Top-level Directory:
  • Renamed: src → app
  • Moved: core → common
• Module Adjustments:
  • Moved: core/exception.py → models/exception.py
  • Relocated:
    • settings/dependency_injection.py → app/di/dependency_injection.py
    • settings/unit_of_work.py → app/di/unit_of_work.py
• Spelling & Directory Corrections:
  • Renamed: src/deliveries/graphql/pokomon → app/deliveries/graphql/pokemon

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Original Structure (v2):

src/
├── core/
│   ├── exception.py
│   └── ...
├── deliveries/
│   ├── graphql/
│   │   └── pokomon/  # Note the misspelling here
│   │       └── ...
│   └── ...
├── settings/
│   ├── dependency_injection.py
│   ├── unit_of_work.py
│   └── ...
└── ...

Updated Structure (v3):

src/
├── app/
│   ├── deliveries/
│   │   ├── graphql/
│   │   │   └── pokemon/  # Spelling corrected
│   │   │       └── ...
│   │   └── ...
│   ├── di/
│   │   ├── dependency_injection.py
│   │   └── unit_of_work.py
│   └── ...
├── common/
│   └── ...
├── models/
│   ├── exception.py
│   └── ...
└── ...