Sample configuration with meaningful defaults for use in Docker and Docker Compose

This is a Sub-Task of aura#112 (closed)

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Such configuration should allow some essential config options be set by environment variables. Essential options are common Docker Compose system values (e.g. audio devices or file paths used in other services too) or values which are most likely changed by end-users.

All config options which are not changed in default setups, should have some good default values. They can be overridden, when required in special setups.

A good example for such file is the Tank - Docker Config