chore(examples): add GPU passthrough support to container backend example

[muzzlol]

What this PR does / why we need it:

Add runtime NVIDIA GPU detection to automatically enable GPU passthrough when available.
Relates to kubeflow/sdk#219

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[muzzlol]

cc @kramaranya @andreyvelich

[coveralls]

Pull Request Test Coverage Report for Build 20745945217

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 51.435%

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Totals
Change from base Build 20682374279:	0.0%
Covered Lines:	1237
Relevant Lines:	2405

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💛 - Coveralls