[YUNIKORN-958] Expose node utilisation info in new REST calls

[anuraagnalluri]

What is this PR for?

Introduce a field in the output of the new REST call -- /ws/v1/partition/{partition}/nodes that displays % utilization.

What type of PR is it?

• - Bug Fix
• - Improvement
• - Feature
• - Documentation
• - Hot Fix
• - Refactoring

Todos

What is the Jira issue?

• https://issues.apache.org/jira/browse/YUNIKORN-958

How should this be tested?

Modified node_test.go to include utilized resource checks.

Screenshots (if appropriate)

Questions:

[codecov]

Codecov Report

Merging #363 (3a6c215) into master (5a1c19e) will increase coverage by 4.09%.
The diff coverage is 68.02%.

@@            Coverage Diff             @@
##           master     #363      +/-   ##
==========================================
+ Coverage   63.46%   67.56%   +4.09%     
==========================================
  Files          60       64       +4     
  Lines        5220     9006    +3786     
==========================================
+ Hits         3313     6085    +2772     
- Misses       1747     2685     +938     
- Partials      160      236      +76     

Impacted Files	Coverage Δ
pkg/metrics/init.go	63.15% <0.00%> (+0.19%)	⬆️
pkg/metrics/queue.go	0.00% <0.00%> (ø)
pkg/scheduler/drf_preemption_policy.go	0.00% <0.00%> (ø)
pkg/scheduler/nodes_usage_monitor.go	0.00% <0.00%> (ø)
pkg/scheduler/objects/sorters.go	100.00% <ø> (ø)
pkg/scheduler/scheduler.go	0.00% <0.00%> (ø)
pkg/webservice/webservice.go	28.57% <ø> (+15.66%)	⬆️
pkg/scheduler/context.go	17.52% <30.05%> (+11.25%)	⬆️
pkg/scheduler/objects/allocation.go	97.22% <33.33%> (-2.78%)	⬇️
pkg/metrics/metrics_collector.go	65.90% <46.42%> (-8.01%)	⬇️
... and 88 more

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[manirajv06]

Looks good. Can you assert "utilized" in TestGetPartitionNodes (handlers_test.go) as well?