General purpose camera pipeline in checkbox_support (New)

[tomli380576]

Description

(This PR is the 1st part of the previously implemented automatic gstreamer pipeline PR that was too big)

This PR adds a general purpose pipeline runner run_pipeline in checkbox_support and an example driver code take_photo that takes a photo using this runner

Resolved issues

#1676 <-- was too big for review. The end goal is to have a test job that can enumerate every (device, capability) combination returned by gst-device-monitor and check if each combination can take a photo/record a video/show a viewfinder

Documentation

I drafted a short design doc to explain some of the weirdness/quirks in the code that might not be fully explained by the comments. Hopefully this helps with the review :)

Tests

Unit tests. Also tested on real devices with USB cameras using the following driver code

if __name__ == "__main__":
    Gst.init([])
    # replace the element with what's available on your system
    elem = Gst.parse_launch("pipewiresrc target-object=47")
    assert isinstance(elem, Gst.Element)
    take_photo(elem, file_path=Path("/home/ubuntu/photo.jpeg"), delay_seconds=3)

Intel MIPI are expected to fail for now since they are only accessible with v4l2src, which isn't exposed in DeviceMonitor. (aside: I think the desktop team is currently backporting this fix from pipewire, if this gets backported then MIPIs will all work without special treatment or explicitly using v4l2src)

This also plays well with checkbox timeout:

# normal termination
timeout(10)(take_photo)(elem, file_path=Path("/home/ubuntu/photo.jpeg"), delay_seconds=3)
# force stop
timeout(3)(take_photo)(elem, file_path=Path("/home/ubuntu/photo.jpeg"), delay_seconds=10)

[codecov]

Codecov Report

Attention: Patch coverage is 93.08176% with 11 lines in your changes missing coverage. Please review.

Project coverage is 49.81%. Comparing base (c52cf57) to head (0c5d90c).
Report is 133 commits behind head on main.

Files with missing lines	Patch %	Lines
...ckbox-support/checkbox_support/camera_pipelines.py	93.08%	6 Missing and 5 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1741      +/-   ##
==========================================
+ Coverage   49.26%   49.81%   +0.55%     
==========================================
  Files         373      377       +4     
  Lines       40434    40931     +497     
  Branches     6830     6930     +100     
==========================================
+ Hits        19921    20391     +470     
- Misses      19785    19793       +8     
- Partials      728      747      +19     

Flag	Coverage Δ
checkbox-support	64.69% <93.08%> (+2.71%)	⬆️

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