speed up system fetch

[amarnath-ac]

1. Use one WS-Man setup per system request to remove extra overhead.
2. Cache static hardware and version data for 5 minutes, while keeping power, features, and boot data live.

[codecov]

Codecov Report

❌ Patch coverage is 12.38095% with 92 lines in your changes missing coverage. Please review.
✅ Project coverage is 42.81%. Comparing base (7f7e804) to head (45374ad).

Files with missing lines	Patch %	Lines
internal/usecase/devices/system_data.go	0.00%	70 Missing ⚠️
redfish/internal/usecase/wsman_repo.go	0.00%	22 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##           redfish    #1055      +/-   ##
===========================================
- Coverage    42.98%   42.81%   -0.18%     
===========================================
  Files          153      154       +1     
  Lines        14853    14923      +70     
===========================================
+ Hits          6385     6389       +4     
- Misses        7888     7954      +66     
  Partials       580      580              

☔ View full report in Codecov by Harness.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.