Python: Add user agent to OpenAI and OpenAPI headers (#3488)

### Motivation and Context

Replaces: #3074

This PR adds the User-Agent header "Semantic Kernel" to calls made to
OpenAI/Azure OpenAI and OpenAPI calls.

### Description

* Addition of telemetry.py file containing telemetry constants
* ability to disable Azure/OpenAI telemetry with an environment variable
called AZURE_TELEMETRY_DISABLED

### 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: Devis Lucato <[email protected]>

python/.vscode/extensions.json

@@ -0,0 +1,7 @@
+{
+  // See https://go.microsoft.com/fwlink/?LinkId=827846
+  // for the documentation about the extensions.json format
+  "recommendations": [
+    "littlefoxteam.vscode-python-test-adapter"
+  ]
+}

python/.vscode/launch.json

@@ -0,0 +1,16 @@
+{
+    // Use IntelliSense to learn about possible attributes.
+    // Hover to view descriptions of existing attributes.
+    // For more information, visit: https://go.microsoft.com/fwlink/?linkid=830387
+    "version": "0.2.0",
+    "configurations": [
+        {
+            "name": "Python: Current File",
+            "type": "python",
+            "request": "launch",
+            "program": "${file}",
+            "console": "integratedTerminal",
+            "justMyCode": true
+        }
+    ]
+}

python/.vscode/settings.json

@@ -23,4 +23,10 @@
     ],
     "python.testing.unittestEnabled": false,
     "python.testing.pytestEnabled": true,
+    "pythonTestExplorer.testFramework": "pytest",
+    "pythonTestExplorer.pytestPath": "poetry",
+    "pythonTestExplorer.pytestArguments": [
+        "run",
+        "pytest"
+    ],
 }