fix(controller): Optimize logic for detach VG from VM for cases with large number of VGs

[thunderboltsid]

We optimize the logic and add some guardrails

• Add a timeout on the context for polling
• Increase the polling interval to 5s
• Set immediate polling to false to reduce likelihood of a 404 on tasks
• Call detachVG one after the other and build a list of tasks
• wait for all tasks in the list to reach a terminal state

[codecov]

Codecov Report

Attention: Patch coverage is 7.14286% with 13 lines in your changes missing coverage. Please review.

Project coverage is 33.00%. Comparing base (5d63d09) to head (69f7b5b).
Report is 1 commits behind head on main.

Files	Patch %	Lines
controllers/nutanixmachine_controller.go	12.50%	7 Missing ⚠️
controllers/helpers.go	0.00%	6 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #477      +/-   ##
==========================================
+ Coverage   32.56%   33.00%   +0.43%     
==========================================
  Files          17       17              
  Lines        1833     1809      -24     
==========================================
  Hits          597      597              
+ Misses       1216     1192      -24     
  Partials       20       20              

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