Global refactoring of the project to use poetry and implement tests,

fixing bugs, changing the handling of dto and db models, preparing to
add new functionality

library_service/models/dto/book.py

@@ -0,0 +1,30 @@
+from sqlmodel import SQLModel
+from pydantic import ConfigDict
+from typing import Optional, List
+
+class BookBase(SQLModel):
+    title: str
+    description: str
+
+    model_config = ConfigDict( #pyright: ignore
+        json_schema_extra={
+            "example": {
+                "title": "book_title",
+                "description": "book_description"
+            }
+        }
+    )
+
+class BookCreate(BookBase):
+    pass
+
+class BookUpdate(SQLModel):
+    title: Optional[str] = None
+    description: Optional[str] = None
+
+class BookRead(BookBase):
+    id: int
+
+class BookList(SQLModel):
+    books: List[BookRead]
+    total: int