Describe the bug

Set OCIS_CORS_ALLOW_ORIGINS="https:/foobar.com" when OCIS_URL=https://something.else

Steps to reproduce

1. create an upload and use tus from https:/foobar.com (this is a cross origin scenario!)

Expected behavior

The upload works

Actual behavior

The upload fails because the OPTIONS request on /data doesn#t return thre right CORS header.

Responses on other routs contain this header, while /data doesn't:
Access-Control-Allow-Origin: https:/foobar.com

Setup

oCIS 5.0.0-rc.3 deployed with the oCIS Chart from next (owncloud/ocis-charts@ebbd8c0)