feat+test: nic attribute modification

[dominikvagner]

connected to: #385

After extensive testing on my part and a joint investigation with @grafuls, this feature cannot be fully implemented in the current state of our lab, because of our iDRAC setup/versions.
Getting a list of attributes for specific NICs is working as it should along with getting information about a specific attribute. (The same way as we do it for BIOS attributes.)
Setting attributes though does not work, even if the somewhat incomplete feeling iDRAC documentation about this use case says it should for versions 5.x.x.x (testing was done against 5.10.50.0 as the newest version available to us).
Neither my attempt at solving this or the reference script from Dell works.
In our case the end-point accepting the setting of attributes shows no supported attributes to set.

The getting functionality was implemented and tested. The setting of attributes was made as a draft implementation supposed to completed in the future, when the environment will allow for it.

[codecov]

Codecov Report

Attention: 78 lines in your changes are missing coverage. Please review.

Comparison is base (5a22209) 91.21% compared to head (c829d7d) 88.57%.
Report is 2 commits behind head on development.

Files	Patch %	Lines
src/badfish/main.py	56.90%	78 Missing ⚠️

Additional details and impacted files

@@               Coverage Diff               @@
##           development     #392      +/-   ##
===============================================
- Coverage        91.21%   88.57%   -2.64%     
===============================================
  Files                5        5              
  Lines             2174     2355     +181     
===============================================
+ Hits              1983     2086     +103     
- Misses             191      269      +78     

Flag	Coverage Δ
unittests	88.57% <56.90%> (-2.64%)	⬇️

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[sadsfae]

@grafuls should we look to merge this through our branches to release?

[grafuls]

Don't want to merge this until we test with a greater FW version than 5.10.50.0 since by our findings with @dominikvagner this doesn't work there.
Parked till the next FW update.

[grafuls]

Closing in lieu of PR #402 which includes test fixes and documentation