Raisl 5.1 removes support for non-keyword arguments in `#process`,
`#get`, `#post`, `#patch`, `#put`, `#delete`, and `#head` for the
`ActionDispatch::IntegrationTest` and `ActionController::TestCase`
classes. This means we have to add `params` everywhere in the controller
tests.
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
