✨(models/api) add link access reach and role

Link access was either public or private and was only allowing readers.

This commit makes link access more powerful:
- link reach can be private (users need to obtain specific access by
  document's administrators), restricted (any authenticated user) or
  public (anybody including anonymous users)
- link role can be reader or editor.

It is thus now possible to give editor access to an anonymous user or
any authenticated user.

CHANGELOG.md

@@ -11,6 +11,7 @@ and this project adheres to
 
 ## Added
 
+- ✨Add link public/authenticated/restricted access with read/editor roles #234
 - ✨(frontend) add copy link button #235
 - 🛂(frontend) access public docs without being logged #235
 
@@ -148,4 +149,4 @@ and this project adheres to
 [1.2.0]: https://github.com/numerique-gouv/impress/releases/v1.2.0
 [1.1.0]: https://github.com/numerique-gouv/impress/releases/v1.1.0
 [1.0.0]: https://github.com/numerique-gouv/impress/releases/v1.0.0
-[0.1.0]: https://github.com/numerique-gouv/impress/releases/v0.1.0
+[0.1.0]: https://github.com/numerique-gouv/impress/releases/v0.1.0