feat: nodeclaim.spec.minimumPriceImprovementPercent

[wmgroot]

Fixes #1440
Implementation component of #1433.

Description
This PR adds a configurable MinimumPriceImprovementPercent to the NodeClaim spec. This allows users control over how large of a cost improvement should be required for consolidation to disrupt pods operating on a node to replace it with a cheaper alternative.

How was this change tested?
TBD. This PR is currently a draft for implementation discussion.

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

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[coveralls]

Pull Request Test Coverage Report for Build 10290317478

Details

• 7 of 43 (16.28%) changed or added relevant lines in 3 files are covered.
• 6 unchanged lines in 2 files lost coverage.
• Overall coverage decreased (-0.2%) to 77.637%

---

Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
pkg/apis/v1/zz_generated.deepcopy.go	1	5	20.0%
pkg/controllers/disruption/consolidation.go	6	18	33.33%
pkg/controllers/disruption/events/events.go	0	20	0.0%

Files with Coverage Reduction	New Missed Lines	%
pkg/controllers/disruption/drift.go	2	89.66%
pkg/controllers/disruption/consolidation.go	4	81.1%

Totals
Change from base Build 10289351631:	-0.2%
Covered Lines:	8898
Relevant Lines:	11461

---

💛 - Coveralls

[github-actions]

This PR has been inactive for 14 days. StaleBot will close this stale PR after 14 more days of inactivity.

[ellistarn]

I think this one makes sense at the NodePool level, rather than the NodeClaim level. This is because the decision to consolidate is at the pool level, unlike expiry/tgp, which make sense outside of the context of a pool (i.e. standalone nodeclaim).

WDYT?

[wmgroot]

I put it in NodeClaim because I think it could be helpful to have the flexibility to set different improvement thresholds for each NodeClaim in a shared NodePool. The existing candidate filtering logic already considers the price of each NodeClaim individually, so there's no added complexity there.

[github-actions]

This PR has been inactive for 14 days. StaleBot will close this stale PR after 14 more days of inactivity.