Enhance DHCP functionality by adding lease timeout support

[NVShawn]

Description

This PR enhances the feature added in #3662 to allow for non-infinite dhcp lease times.

So we do not break current installs, we keep the 'infinite' lease time as default but allow for a config to change the lease times to non-infinite values.

We've had issues with VMs with the lease set to infinite where they never check to see if their IP is still available, so we get IP conflicts. In our environment, with a combination of very short lived and long lived VMs and constrained IP address, we have to rely on IP address re-use and lease timeouts. This change allows us to configure our IP lease timeouts without modifying default behavior.

Types of changes

• Breaking change (fix or feature that would cause existing functionality to change)
• New feature (non-breaking change which adds functionality)
• Bug fix (non-breaking change which fixes an issue)
• Enhancement (improves an existing feature and functionality)
• Cleanup (Code refactoring and cleanup, that may add test cases)
• Build/CI
• Test (unit or integration test code)

Feature/Enhancement Scale or Bug Severity

Feature/Enhancement Scale

• Major
• Minor

Bug Severity

• BLOCKER
• Critical
• Major
• Minor
• Trivial

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