Provide a installable tarball that contains the latest changes

For installing the app ( on docker images ) - ownCloud expects to find a tarfile with 
```
testing
  - dir1 
  - dir2
```

But github provides everything in a top folder. We thus require a build app that can be used to install it in a docker image

## Possible Solutions
- move the codebase into a sub-folder (easiest )
- create a release pipeline 