docker-compose for a complete Opencast with Tobira

[KatrinIhler]

Create a docker file that allows to easily spin up an Opencast with Tobira to try things out.

Edit: Also database, Opensearch, with basic configuration. Also documentation for beginners (e.g. smaller institution) needed.

[mtneug]

I would see this in opencast/community-integrations instead of here. This would need automation for creating Tobira container images.

[KatrinIhler]

Waiting on #243