detectors/openstack/nova: add Openstack Nova resource detector

[paulojmdias]

Ports the Openstack Nova resource detector from processor/resourcedetectionprocessor/internal/openstack/nova in
opentelemetry-collector-contrib to a new standalone Go module go.opentelemetry.io/contrib/detectors/openstack/nova.

Also registers the detector in detectors/autodetect as IDOpenStackNova ("openstack.nova").

I'm proposing to be a codeowner of this detector as I am currently on the collector-contrib side.

Fixes #8965
Relates #8940

[codecov]

Codecov Report

❌ Patch coverage is 95.45455% with 4 lines in your changes missing coverage. Please review.
✅ Project coverage is 84.6%. Comparing base (b0f0785) to head (f7729d3).

Files with missing lines	Patch %	Lines
detectors/openstack/nova/nova.go	95.4%	2 Missing and 2 partials ⚠️

Additional details and impacted files

@@          Coverage Diff          @@
##            main   #9486   +/-   ##
=====================================
  Coverage   84.5%   84.6%           
=====================================
  Files        203     204    +1     
  Lines      16805   16893   +88     
=====================================
+ Hits       14215   14299   +84     
- Misses      2110    2112    +2     
- Partials     480     482    +2     

Files with missing lines	Coverage Δ
detectors/autodetect/autodetect.go	87.1% <100.0%> (+0.1%)	⬆️
detectors/openstack/nova/nova.go	95.4% <95.4%> (ø)

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