Application not working when installed only on subwiki

[oanalavinia]

Steps to reproduce:

1. Install the application on a subwiki
   Note that the application has 2 modules that need to be installed on farm, see the first 2 from the dependencies tab:

After installing these 2, you can proceed with installing the application on the chosen subwiki

2. Add a license
3. Configure the application by adding a Collabora server address and enable it
4. Try to edit an attachment using Collabora

Expected result: it works without problems
Actual result: the attachment is not loaded and an error is displayed

[oanalavinia]

The not found error is not semantically correct, since right now this is thrown when an error occurs, which happens here for this case
The actual problem comes from #10

[oanalavinia]

Fixed by #10