Use Linq2DB for better database stuff

[Atulin]

https://linq2db.github.io

The EF Core extension allows, among others:

• Updating without fetching

  db.Product
      .Where(p => p.ProductID == product.ProductID)
      .Set(p => p.Name, product.Name)
      .Set(p => p.UnitPrice, product.UnitPrice)
      .Update();

• Deleting without fetching

  db.Product
      .Where(p => p.ProductID == product.ProductID)
      .Delete();

[Atulin]

Done for blogposts with https://github.com/Atulin/Ogma/commit/d568ff5033c9198455668cb879a006a35b9cdca2

[Atulin]

Done for chapters with https://github.com/Atulin/Ogma/commit/23bafccca218bd333fa773e03f68d171a0d3b9f9

[Atulin]

No longer necessary with the recent additions to EF Core like .ExecuteUpdateAsync() and .ExecuteDeleteAsync()