+Add ALE options mimicking Hycom

  Added a number of options to MOM_ALE to mimic options that are found in
Hycom.  By default, all answers are bitwise identical, but there are several
new runtime parameters.  The code changes include:

 . Added the ability to use a different remapping scheme for velocities than
   for tracers, using the new runtime parameter VELOCITY_REMAPPING_SCHEME

 . Added the new runtime option PARTIAL_CELL_VELOCITY_REMAP to use partial cell
   thicknesses for remapping at velocity points, which triggers a call to the
   new internal routine apply_partial_cell_mask.

 . Added the new internal routine mask_near_bottom_vel to allow MOM6 to mimic
   Hycom in zeroing out the velocities in thin layers in a bottom boundary
   layer with a thickness given by the new runtime parameter
   REMAP_VEL_MASK_BBL_THICK, while the definition of thin is specified by
   REMAP_VEL_MASK_H_THIN.  Setting these to be negative (as is the default)
   avoids this.

 . Modified the interface to remap_all_state_vars to take just the ALE_CS, which
   then provides the remapping control structure that is appropriate for the
   tracers or velocities, rather than also passing this in as an argument.

 . Eliminated some unnecessary internal variables, and added others to be
   more explicit avoid array syntax copies in arguments.