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/author.py

@@ -0,0 +1,25 @@
+from sqlmodel import SQLModel
+from pydantic import ConfigDict
+from typing import Optional, List
+
+class AuthorBase(SQLModel):
+    name: str
+
+    model_config = ConfigDict( #pyright: ignore
+        json_schema_extra={
+            "example": {"name": "author_name"}
+        }
+    )
+
+class AuthorCreate(AuthorBase):
+    pass
+
+class AuthorUpdate(SQLModel):
+    name: Optional[str] = None
+
+class AuthorRead(AuthorBase):
+    id: int
+
+class AuthorList(SQLModel):
+    authors: List[AuthorRead]
+    total: int