chore(OpenRosa): remove some deprecated endpoints of v1 not called anymore by KPI TASK-1356

[Guitlle]

🗒️ Checklist

1. run linter locally
2. update all related docs (API, README, inline, etc.), if any
3. draft PR with a title <type>(<scope>)<!>: <title> TASK-1234
4. tag PR: at least frontend or backend unless it's global
5. fill in the template below and delete template comments
6. review thyself: read the diff and repro the preview as written
7. open PR & confirm that CI passes
8. request reviewers, if needed
9. delete this section before merging

📣 Summary

The OpenRosa V1 API contains many endpoints that are deprecated because the functionality is no longer needed as a REST API but rather as code utilities and classes, instead. The deleted endpoints are:

• bulk_delete
• bulk_validation_status
• validation_status
• destroy
• enketo
• enketo_edit
• enketo_view

📖 Description

This PR deletes deprecated code, endpoints and tests, from the OpenRosa V1 API

👀 Preview steps

No preview steps are needed, all unit tests are passing.

[noliveleger]

LGTM, but we need to add a REMOVALS.md like we did in KoboCAT repo.
https://github.com/kobotoolbox/kobocat/blob/main/REMOVALS.md

Please have a look at README in KoboCAT to do something similar in kobo/apps/openrosa/README which would points to a REMOVALS.md