For the following issue:
- https://github.com/fleetdm/fleet/issues/41419
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## Summary by CodeRabbit
* **Chores**
* Updated tooling and documentation wording across scripts, utilities,
and infrastructure files to reflect the product terminology change from
“teams” to “fleets” (references now note “fleets” and indicate the
former “teams” naming).
<!-- end of auto-generated comment: release notes by coderabbit.ai -->
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Co-authored-by: Rachael Shaw <r@rachael.wtf>
* Remove username from UI code
* Remove username from tests
* Remove username from database
* Modify server endpoints for removing username
* Implement backend aspects of removing username
* Update API docs
* Add name to fleetctl
* Perform migration to delete any entries with `deleted` set, and
subsequently drop columns `deleted` and `deleted_at`.
* Remove `deleted` and `deleted_at` references.
Closes#2146