Move unsupported xlators to experimental status

[vbellur]

There are translators like crypt, block-device etc. which are not actively supported for various reasons. It would be ideal to have all such unsupported translators in the experimental status so that there's no ambiguity about the support status of such xlators.

xlators can be moved out of experimental status when we actively start supporting them.

[gluster-ant]

A patch https://review.gluster.org/16276 has been posted that references this issue.
Commit message: encryption: Move all xlators to experimental

[gluster-ant]

A patch https://review.gluster.org/16276 has been posted that references this issue.
Commit message: encryption: Move all xlators to experimental

[amarts]

Set of patches posted to handle https://bugzilla.redhat.com/show_bug.cgi?id=1635688 are solving this particular issue. Removing these translators from the codebase is successful, and these are now moved to gluster/glusterfs-xlators repository.