Change Default Account Passwords

[ThomasThelen]

We should avoid using passwords for the default virtuoso accounts, for example dba:dba and dav:dav. We should be setting new passwords during deployment; see this documentation link for more information.

[amoeba]

Totally. I'll toss the docs for the official openlink image we're using in here: https://hub.docker.com/r/openlink/virtuoso-opensource-7. See the "Passwords". section.

When a new database is created, the docker image will use the Environment settings DBA_PASSWORD and DAV_PASSWORD to set passwords for the dba and dav user accounts.

[ThomasThelen]

Completed in #42 ; deployments can manage the password in the environmental variable field