twofactor_backup_codes: going out of maintenance

[DeepDiver1975]

owncloud/twofactor_backup_codes is being archived and will no longer be maintained.
Please update the documentation to remove or deprecate its pages and references.

• Archived repo: https://github.com/owncloud/twofactor_backup_codes
• README archive notice: docs: mark repository as archived and unmaintained twofactor_backup_codes#61

[DeepDiver1975]

Investigated references to twofactor_backup_codes across all built content repos/branches (local Antora cache + live GitHub code search + built public/ output).

Findings

The app was never documented as a feature — no dedicated page, not in the supported-apps list, and the 2FA documentation uses a different app (twofactor_totp) as its example. Its only appearance in any docs repo is as the worked example for finding an app id and running occ market:install, in:

docs-server → modules/admin_manual/pages/configuration/server/occ_commands/app_commands/_market_commands.adoc (present on master, 10.15, 10.16).

Since the tutorial steered readers at the now-archived app's Marketplace page, I swapped the example to twofactor_totp (verified actively maintained, a real Marketplace app, already the canonical 2FA app elsewhere in these docs).

PR: owncloud/docs-server#1560

No pages needed removing. Nothing to change in this aggregator repo.