Interesting Terms parameter is ignored by MLT Component

Currently the More Like This component just ignores the mlt.InterestingTerms parameter ( which is usable by the MoreLikeThisHandler).

Scope of this issue is to fix the bug and add related tests ( which will succeed after the fix )

N.B. MoreLikeThisComponent and MoreLikeThisHandler are very coupled and the tests for the MoreLikeThisHandler are intersecting the MoreLikeThisComponent ones .
It is out of scope for this issue any consideration or refactor of that.
Other issues will follow.

N.B. out of scope for this issue is the distributed case, which is much more complicated and requires much deeper investigations