* Prevent different identities from a same SSO provider from accessing a same account
* Lock auth provider changes behind `ALLOW_UNSAFE_AUTH_PROVIDER_REATTACH=true`
* Rename methods to avoid confusion between OAuth and OmniAuth
Conflicts:
- `.rubocop_todo.yml`:
Upstream fixed a bunch lint issues, and changed the `Max` parameter of the
`Metrics/AbcSize` cop.
Glitch-soc has different code and slightly higher `AbcSize` complexity,
modified the `.rubocop_todo.yml` file accordingly.
- `app/policies/status_policy.rb`:
Upstream changed `account.suspended?` to `account.unavailable?` to prepare
for delete flags. Glitch-soc has additional local-only conditions.
Ported upstream's refactor while keeping glitch-soc's additional condition.
- `app/serializers/initial_state_serializer.rb`:
Upstream refactored a bunch of stuff while glitch-soc has more settings.
Refactored as upstream did while keeping glitch-soc's settings.
