Opportunities for refactoring in GenericContainer

The startup code in GenericContainer seems pretty aggressive in retrying startup failures. I've looked at the code and I'm not sure about the value of some of the things it's doing. I think I may be missing some of the use cases you're trying to support here.

First, there's the inner loop where it waits for the status "running". I've tried this, but I've yet to see a case where a container started up correctly and didn't immediately return "running"... but again, maybe I just haven't seen the use case. It also seems that, since there's no current way to set the container as retrying, if the state is "exited" and the finished at time is not null, it's safe to assume the container will never start up, so we could bail out before the full 30 seconds.

Second, the outer loop, where we retry 3 times. I can't think of a case where the container will fail to start the first time and succeed the second, unless you're starting multiple containers in parallel, or unless the container is flaky - and in the context of an automated test, if something is flaky I'd think that reporting the failure would be more desirable. The retry loop adds complexity, and at least one bug (#102), so I wonder if it would be better to just remove it. Unless, again, there's a use case it supports that I'm not aware of...

Empieza leyendo el código de startup de GenericContainer, centrándote en el bucle interno de espera a que esté en ejecución y en el bucle externo de reintentos de tres intentos descritos en el issue. Determina qué estados de startup y casos de uso admiten estos bucles y, después, valida el comportamiento propuesto con las pruebas existentes y el issue #102 antes de considerar completo el refactor.