FromAppSettings improvements

[marcominerva]

Context / Scenario

The ability to configure KernelMemory using appsettings.json is great, but I think it could be improved.

The problem

Currently, the FromAppSettings extension method is available only in the Service project, so if we want to use this feature in our custom projects, we need to manually copy the code.

Proposed solution

It would be great to have the FromAppSettings extension method as a NuGet package, so that we can use it in every project.
To make this feature more general, we could think of a method like WithConfiguration(IConfiguration source) :

var kernelMemoryBuilder = new KernelMemoryBuilder(builder.Services)
    .WithConfiguration(builder.Configuration);

Importance

would be great to have

[pawarsum12]

Duplicate of #287