Add automatic wait strategy

[lhuet]

Have a fluent API with a wait timeout would be great:

new ElasticsearchContainer().withStartupTimeout(Duration)

[dadoonet]

Actually really similar to #21 (I forgot that I opened this already :) )

[dadoonet]

Interesting. That's actually probably not needed.
We check by default that "something" is running on port 9200. Whatever the status of the other elasticsearch services.

We might have to wait for the status of a specific underlying service though but in that case, we can just implement the HttpWaitStrategy.

I feel like that this issue and #21 are pretty much useless.

[dadoonet]

Now that the project moved to testcontainers as a module, I'm not planning to add more commits as the project will be living here now: https://github.com/testcontainers/testcontainers-java/tree/master/modules/elasticsearch.