Add iteration to TimeUnit

[b-chu]

What does this PR do?

Stack:

• Add Iteration related Events #3019
• Deprecate get_state and remove deprecations #3017
• Add iteration to TimeUnit #3013 ⬅
• Add duration to to_next_epoch #3012

⚠️ Part of a stack created by spr. Do not merge manually using the UI - doing so may have unexpected results.

What issue(s) does this change relate to?

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[snarayan21]

some comments

[snarayan21]

nice, lgtm

[mvpatel2000]

Holding per offline discussion

[b-chu]

✓ Commit merged in pull request #3017