Add gude8210 snmp support

[onurcelep]

Description
Adds power driver integration for GUDE Expert Power Control 8210

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

• PR has been tested

• Man pages have been regenerated

[codecov]

Codecov Report

Attention: Patch coverage is 20.00000% with 28 lines in your changes missing coverage. Please review.

Project coverage is 55.7%. Comparing base (83d306c) to head (47bb5d2).
Report is 11 commits behind head on master.

✅ All tests successful. No failed tests found.

Files with missing lines	Patch %	Lines
labgrid/driver/power/gude8210.py	20.0%	28 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff            @@
##           master   #1636     +/-   ##
========================================
- Coverage    55.8%   55.7%   -0.1%     
========================================
  Files         170     171      +1     
  Lines       13388   13423     +35     
========================================
+ Hits         7471    7478      +7     
- Misses       5917    5945     +28     

Flag	Coverage Δ
3.10	55.7% <20.0%> (-0.1%)	⬇️
3.11	55.7% <20.0%> (-0.1%)	⬇️
3.12	55.7% <20.0%> (-0.1%)	⬇️
3.13	55.6% <20.0%> (-0.1%)	⬇️
3.9	55.7% <20.0%> (-0.1%)	⬇️

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