Python: Agent get_response API (microsoft#10701)

### Motivation and Context

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With the recent push for improving developer's quality of life, we have
decided to make it easier for developers to get started with agents by
introducing a new `get_response` API, that hides the complexity of
interacting with agents when developers are ramping up with the Agent
concept.

### Description

<!-- Describe your changes, the overall approach, the underlying design.
These notes will help understanding how your code works. Thanks! -->
1. Add the `get_response` API on all agent types. This API skips hides
the intermediate steps of the agent execution and only returns the final
results as a single message.
2. Add tests and samples.
3. Updates the `Agent` class to be an `ABC`, and adds `get_response`,
`invoke`, and `invoke_stream` methods as overridable.

### Contribution Checklist

<!-- Before submitting this PR, please make sure: -->

- [x] The code builds clean without any errors or warnings
- [x] The PR follows the [SK Contribution
Guidelines](https://github.com/microsoft/semantic-kernel/blob/main/CONTRIBUTING.md)
and the [pre-submission formatting
script](https://github.com/microsoft/semantic-kernel/blob/main/CONTRIBUTING.md#development-scripts)
raises no violations
- [x] All unit tests pass, and I have added new tests where possible
- [x] I didn't break anyone 😄

---------

Co-authored-by: Evan Mattson <[email protected]>

Author: TaoChenOSU

python/.cspell.json

@@ -25,12 +25,14 @@
     "words": [
         "aeiou",
         "aiplatform",
+        "autogen",
         "azuredocindex",
         "azuredocs",
         "boto",
         "contentvector",
         "contoso",
         "datamodel",
+        "desync",
         "dotenv",
         "endregion",
         "entra",
@@ -64,18 +66,10 @@
         "templating",
         "uninstrument",
         "vectordb",
+        "vectorizable",
         "vectorizer",
         "vectorstoremodel",
         "vertexai",
-        "Weaviate",
-        "qdrant",
-        "huggingface",
-        "pytestmark",
-        "contoso",
-        "opentelemetry",
-        "SEMANTICKERNEL",
-        "OTEL",
-        "vectorizable",
-        "desync"
+        "Weaviate"
     ]
-}
+}

python/samples/README.md

@@ -1,9 +1,10 @@
-## Semantic Kernel Samples
+# Semantic Kernel Samples
 
 | Type                                                                     | Description                                                                                                            |
 | ------------------------------------------------------------------------ | ---------------------------------------------------------------------------------------------------------------------- |
 | [`getting_started`](./getting_started/CONFIGURING_THE_KERNEL.md)         | Take this step by step tutorial to get started with Semantic Kernel and get introduced to the key concepts.            |
 | [`getting_started_with_agents`](./getting_started_with_agents/README.md) | Take this step by step tutorial to get started with Semantic Kernel Agents and get introduced to the key concepts.     |
+| [`getting_started_with_processes`](./getting_started_with_processes/README.md) | Take this step by step tutorial to get started with Semantic Kernel Processes and get introduced to the key concepts.     |
 | [`concepts`](./concepts/README.md)                                       | This section contains focused samples which illustrate all of the concepts included in Semantic Kernel.                |
 | [`demos`](./demos/README.md)                                             | Look here to find a sample which demonstrate how to use many of Semantic Kernel features.                              |
 | [`learn_resources`](./learn_resources/README.md)                         | Code snippets that are related to online documentation sources like Microsoft Learn, DevBlogs and others               |