Migrate to Dotnet Core 6.0 hosting model

[ShaunKrog]

Refers to https://learn.microsoft.com/en-us/aspnet/core/migration/50-to-60?view=aspnetcore-6.0&tabs=visual-studio (Migrate from ASP.NET Core 5.0 to 6.0), which suggests implementing a new streamlined minimal model for booting up the application.

Is your feature request related to a problem? Please describe.
The new .NET 6 minimal hosting model:

• Significantly reduces the number of files and lines of code required to create an app. Only one file is needed with four lines of code.
• Unifies Startup.cs and Program.cs into a single Program.cs file.
• Uses [top-level statements] (https://learn.microsoft.com/en-us/dotnet/csharp/fundamentals/program-structure/top-level-statements) to minimize the code required for an app.
• Uses global using directives to eliminate or minimize the number of using statement lines required.

Applying migrations through EF Core 6.0 results in the application starting before migrations are applied. See https://stackoverflow.com/questions/70368401/why-does-dotnet-ef-migrations-add-start-my-application

Describe the solution you'd like

• Move from WebHost builder to WebApplication builder to bootstrap application
• Merge startup and program classes