Enhancement: Add web extensions to the ocis_full example

We added some of the web extensions from ownCloud to the ocis_full docker compose example.

- importer
- draw-io
- external-sites
- json-viewer
- unzip
- progressbars

These can be enabled in the .env file one by one.

Read more about ocis extensions in https://github.com/owncloud/web-extensions/blob/main/README.md

https://github.com/owncloud/ocis/pull/10399
