Make Collabora server usable on subwikis after adding the main wiki as an accepted domain

[oanalavinia]

The Collabora Online docker server needs to have defined the domains which are accessing their services, see #6

Steps to reproduce:

1. Add the main wiki domain as an accepted domain on the Collabora server
2. Go to a subwiki and try to edit an office document

Expecte result:
You can edit the document
Actual result:
You cannot edit the document due to an authorization problem

The workaround is to add the subwiki domain to the docker configuration as well, but this isn't nice when you have many subwikis.
Also, the Collabora server might accept only a specific number of hosts (to check) and a new server will be needed in order to be able to edit on all subwikis.