Move database configuration to config file instead of hardcoding

[StefH]

Use:

services.AddDbContext<MyHotelDbContext>(options => options.UseSqlServer(Configuration["ConnectionStrings:MyHotelDb"]));

And define appsettings .Development.json like:

"ConnectionStrings": {
    "MyHotelDb": "Data Source=(localdb)\\MSSQLLocalDB;Initial Catalog=MyHoteDbl;Trusted_Connection=True;MultipleActiveResultSets=true"
  },