moves common/time.go to common/dttm/dttm.go, and renames many of the consts and funcs with names that better explain their design and intent of usage.
Only code movement, no logical changes.
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#### Does this PR need a docs update or release note?
- [x] ⛔ No
#### Type of change
- [x] 🧹 Tech Debt/Cleanup
#### Test Plan
- [x] ⚡ Unit test
- [x] 💚 E2E