hardcoded images

[mabn]

Some classes use hardcoded images which makes it impossible to use testcontainers with private registry. In particular richnorth/ambassador:latest.

It should be adjustable, e.g. via a config file or env variable. Or with additional parameters to junit rules.

Also:
richnorth/vnc-recorder:latest

[rnorth]

@mabn thanks, yes, it's probably about time to make these configurable. I think a config file on the classpath would be the right answer.