Add Dockge to OVA

[teon]

Description

In order to easly manage Defguard components (update, see logs etc) please add Dockge (https://github.com/louislam/dockge) to compose.
Please remember to:

1. Expose the directory where defguard directory with compose is as a volume eg. /srv/:/opt/stacks
2. And then - DOCKGE_STACKS_DIR=/opt/stacks - Dockge only manages container to which it has access to it's docker compose.
3. Would be perfect to have initial Dockge database (user/pass) to skip the initial config.