support/testing: add fastapi runtime test

Add a runtime test for fastapi. Use uvicorn as the asgi server
application as does the fastapi hello world example [1].

Fastapi depends on PydanticV2 now which is written in rust so we need to
run the test on armv7.

[1] https://fastapi.tiangolo.com/tutorial/first-steps/

Signed-off-by: Marcus Hoffmann <bubu@bubu1.eu>
[Arnout:
 - fix flake8 errors
support/testing/tests/package/sample_python_fastapi.py:5:1: E302 expected 2 blank lines, found 1
support/testing/tests/package/sample_python_fastapi.py:8:1: W391 blank line at end of file
 - Remove BR2_CCACHE (as requested by Marcus).
 - Add a comment explaining that this also tests uvicorn and pydantic.
 - Re-try wget in a loop instead of a fixed timeout of 30 seconds.
 - Add a DEVELOPERS entry.
]
Signed-off-by: Arnout Vandecappelle <arnout@mind.be>

support/testing/tests/package/sample_python_fastapi.py

@@ -0,0 +1,8 @@
+from fastapi import FastAPI
+
+app = FastAPI()
+
+
+@app.get("/")
+async def root():
+    return {"message": "Hello World"}