Move integration tests into a new Maven module

[Francesco Mari <ma...@gmail.com>]

Hi all,

while moving the Segment Store into its own bundle, I figure out that some
(integration) tests in oak-core create cyclic dependencies between the new
Segment Store bundle and oak-core itself.

In OAK-3862 I suggest to move integration tests into a separate Maven
module to avoid cyclic dependencies. I can take care of every test
involved, but since it's a cross-cutting modification that could
potentially involve the work of all of you, I would like to hear your
opinion about this.

Are you in favour of this change?