SemanticKernel: Correcting non-standard way of working with PromptExecutionSettings

- Async loading supports cancellation through a `CancellationToken`. If loading is cancelled an `OperationCanceledException` is thrown.  If it fails for another reason a `LoadWeightsFailedException` is thrown.
 - Updated examples to use `LoadFromFileAsync`

The extension of PromptExecutionSettings is not only for ChatCompletion, but also for text completion and text embedding.

* LLama.Examples: RepoUtils.cs → ConsoleLogger.cs

* LLama.Examples: Examples/Runner.cs → ExampleRunner.cs

* LLama.Examples: delete unused console logger

* LLama.Examples: improve splash screen appearance

the llama_empty_call() no longer shows configuration information on startup, but it will display it automatically the first time a model is engaged

* LLama.Examples: Runner → ExampleRunner

* LLama.Examples: improve model path prompt

The last used model is stored in a config file and is re-used when a blank path is provided

* LLama.Examples: NativeApi.llama_empty_call() at startup

* LLama.Examples: reduce console noise when saving model path

- Renamed files and updated namespaces in Examples folder.
- Moved files from NewVersion folder to Examples folder.
- Removed TestRunner.cs file.
- Updated Runner.cs to include new examples.
- Update Program.cs to use the new Runner class instead of NewVersionTestRunner
- Update LLama.Examples namespace in Program.cs
- Update await NewVersionTestRunner.Run() in Program.cs to await Runner.Run()