Refactor existing link endpoints to avoid collisions with the existing ones

[imsdu]

Motivation New link endpoints will be introduced and to avoid collisions with existing and points we need to change them

Acceptance criteria

1. For files, the endpoint will be under: /link/files/[org]/[project]/[?id]?[?rev]
2. Mention to register are refactored to link
3. Documentation is written

Implementation notes To make it easier, those endpoint can be implemented in a dedicated route