Consider moving MoveIt cfgs to a sub dir

[gavanderhoorn]

See gavanderhoorn/fanuc@move_around.

Store MoveIt configuration packages and plugin packages in a moveit sub directory of the repository.

This makes no difference to Catkin or rospkg, but makes it much easier to see for which robot series this repository has support, as only the various support packages are at the top-level (and the single driver and resources package).

[gavanderhoorn]

It also reduces the amount of scrolling needed to get to the readme :)

[gavanderhoorn]

I think I'm going to do this, at least here in this repository.

Top-level structure goes from 47 directories down to 20, which is more than a 50% reduction.

Due to the naming scheme we use for support packages, even new users should be able to immediately see whether a particular series is supported, as all the fanuc_*_support packages will be immediately visible.