Added

Migration plan overview:
- Describes the order of events of a migration setup destination > users > sample migration > waves
Migration Wave Workflow:
- Describes the repeating cycle of a migration wave
Migration Info for end users:
- Describes what customers should communicate with their users during each phase of a migration

Moved From Congregate Customer folder

These two md files are more suited to be with these issues that should be present in each migration customer collab: