Allow specifying custom metric value for fabric interfaces etc

[indy-independence]

Also allow some extra fields like mtu, tags to fabric interfaces. Fix docs for radius settings

[codecov]

Codecov Report

Attention: Patch coverage is 33.33333% with 4 lines in your changes missing coverage. Please review.

Project coverage is 64.55%. Comparing base (b0d4855) to head (fe282d6).
Report is 1 commits behind head on develop.

Files	Patch %	Lines
src/cnaas_nms/devicehandler/sync_devices.py	20.00%	4 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##           develop     #357      +/-   ##
===========================================
+ Coverage    64.45%   64.55%   +0.09%     
===========================================
  Files           74       74              
  Lines         8075     8080       +5     
===========================================
+ Hits          5205     5216      +11     
+ Misses        2870     2864       -6     

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[sonarcloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarCloud