Feature: Expand Cover contract with expireCover

[MilGard91]

Context

When cover expires is no way to refresh the capacity before the bucket expires

Issue: #863

Changes proposed in this pull request

Added expireCover that will expire cover even though the bucket didn't expire, so we can use the capcaity.

Test plan

Added tests for expireCover function in integration tests.

Checklist

• Rebased the base branch
• Attached corresponding Github issue
• Prefixed the name with the type of change (i.e. feat, chore, test)
• Performed a self-review of my own code
• Followed the style guidelines of this project
• Made corresponding changes to the documentation
• Didn't generate new warnings
• Didn't generate failures on existing tests
• Added tests that prove my fix is effective or that my feature works

Review

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