driver: usbvideodriver: add support for overlaying FPS

[a3f]

Description

We encourage addition of multiple quality settings for USB Video
devices, but there is no easy way to get feedback how many frames per
second are actually processed on the receiver side, which could
influence which quality settings would be chosen for Labgrid, especially as connection over USB 2.0/USB 3.0 can impact what frame rates we can achieve.

To allow for an easy evaluation of video devices and how they're
connected, expose the newly added fps feature in USBVideoDriver as
--fps command line option.

• what do you use the feature for?

Check that I indeed am able to get the framerate configured in the quality

• how does labgrid benefit as a testing library from the feature?

Makes it easier to evaluate cameras/HDMI grabbers

• how did you verify the feature works?

I ran the command with and without --fps and with the different quality settings

• if hardware is needed for the feature, which hardware is supported and which
  hardware did you test with?

I tested against the Guermok HDMI grabber added in #1709

Checklist

• Documentation for the feature
• Tests for the feature
• The arguments and description in doc/configuration.rst have been updated
• Add a section on how to use the feature to doc/usage.rst
• Add a section on how to use the feature to doc/development.rst

The existing arguments aren't documented/test either. The `--fps`` is documented in the help text.

[a3f]

I rebased on top of #1709 to avoid a trivial conflict in the CHANGES.rst

[Bastian-Krause]

@a3f Could you take a look at the ruff format errors?

[codecov]

Codecov Report

❌ Patch coverage is 33.33333% with 4 lines in your changes missing coverage. Please review.
✅ Project coverage is 55.6%. Comparing base (c8f1f41) to head (c0166da).
⚠️ Report is 4 commits behind head on master.
✅ All tests successful. No failed tests found.

Files with missing lines	Patch %	Lines
labgrid/driver/usbvideodriver.py	33.3%	2 Missing ⚠️
labgrid/remote/client.py	33.3%	2 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff            @@
##           master   #1710     +/-   ##
========================================
- Coverage    55.6%   55.6%   -0.1%     
========================================
  Files         172     172             
  Lines       13462   13466      +4     
========================================
+ Hits         7491    7492      +1     
- Misses       5971    5974      +3     

Flag	Coverage Δ
3.10	55.6% <33.3%> (-0.1%)	⬇️
3.11	55.6% <33.3%> (-0.1%)	⬇️
3.12	55.6% <33.3%> (-0.1%)	⬇️
3.13	55.6% <33.3%> (-0.1%)	⬇️
3.9	55.6% <33.3%> (-0.1%)	⬇️

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[a3f]

@a3f Could you take a look at the ruff format errors?

Sorry, I mistakenly thought it was "just" coverage like in the other PR.