OR-733 Adds the workflow to the membershiprequest community object

* Add a `workflow` field in the `membershipRequests` field in the
`community` model.
* Add a `workflow` parameter in the core function.
* Update tests
OR-684 Add a new route /api/user/notifications/read?ids[]=
Merge pull request #490 in OR/rse from ~RPIGNOLET/rse:OR-733 to master

* commit 'a6418bb43f03f1b683c93f7feedaf7286a64a7dd':
  OR-733 Adds the workflow to the membershiprequest community object
Merge pull request #491 in OR/rse from ~SLEMAISTRE/rse:OR-684 to master

* commit '64d79a3a5f9121b44163ffa98603e4a1371c32ef':
  OR-684 Add a new route /api/user/notifications/read?ids[]=