ClusterOverview: Improve prometheus query for CPU Capacity

[mareklibra]

and fix Capacity tests.

[coveralls]

Pull Request Test Coverage Report for Build 1013

• 1 of 1 (100.0%) changed or added relevant line in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.2%) to 87.448%

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Totals
Change from base Build 1010:	0.2%
Covered Lines:	3072
Relevant Lines:	3365

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💛 - Coveralls

[coveralls]

Pull Request Test Coverage Report for Build 1255

• 1 of 1 (100.0%) changed or added relevant line in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.1%) to 87.507%

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Totals
Change from base Build 1251:	0.1%
Covered Lines:	3083
Relevant Lines:	3376

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💛 - Coveralls

[rawagner]

@mareklibra is there any PR for web-ui which changes CPU query to get CPU usage in % ? Or maybe you want to use cpuUtilization instead of cpuUsed ?

[mareklibra]

@rawagner , I forgot to push :-) kubevirt/web-ui#263