[hibernate-dev] [OGM] Move container integration test to a separate default test cycle

[Emmanuel Bernard]

This is a follow up on
https://github.com/hibernate/hibernate-ogm/pull/307#issuecomment-38453092

We keep piling up new backends, new containers to test and new rules
checked at build time. A consequence is that it is becoming less and
less pleasant to work on OGM.

You can see that n version of Naked+WF+EAP+... multiplied by m backends
simply will make this project horrendously slow to contribute to.
I imagine n = 3 or 4 and m = 10 in a medium term.

I see two options that would keep us around for a while:

1. Make the container integration tests only run with a specific option
   activated on the CI.
2. Move the container integration tests outside in a different repo
   altogether.

I do prefer 1.

Emmanuel