Users currently have no way to be notified when new conferences are
published on an OSEM instance. This adds an RSS 2.0 feed endpoint at
/feed.rss that lists all conferences ordered by creation date.
The feed action is excluded from CanCanCan authorization so it remains
publicly accessible without authentication, similar to the existing
calendar endpoint.
Also adds an RSS subscribe link to the conferences index page and an
auto-discovery <link> tag in the application layout so RSS readers can
detect the feed automatically.
Fixes#3543
It used to be a partial inside #index, but having their own page
yields some extra benefits:
- Performance: Move logic from the view to the controller
- Theres' no need to go extra steps inside the :index view
- UI: Remove the extra 'Upcoming Conferences' when the system needs
to start the flow of the creation of the first user
When viewing a conference, the Instance Name in the header points to
/organizations. On the organizations index, there's a button to see
conferences, but it does nothing. This makes it easy for public users to
get lost.
This commit:
* Adds a function to the organizations controller to show child
conferences
* Adds a public permission to see conferences through an organization
* Represents a subset of conferences, reusing conferences/index view,
for the organization
