[Announcements] Allow announcements to be sent to other targets

[tudoramariei]

Description

Allow filtering the target of an announcement based on role; this is additional to the existing filtering by the department.

Test environment

On the Web interface, in an organization's admin interface.

Preconditions

You need an organization with different departments and roles.

Steps of Reproduction

1. Go to /announcements/add to create a new announcement
2. In the Target section, select the target group of the announcement

Expected Result

There should also be a section with Roles that can be filtered.

Actual Result

An admin can only select to filter through the departments of the NGO.

Screenshots