(*)bugfixes for internal tides

- TKE_itidal_input values are set to zero where it is not applied to
  the model so that diagnostics are consistent

- removed useless halo updates

- diagnose energy loss terms as dE/dt instead of equivalent loss rate
  to properly close energy budget

- tot_vel_btTide2 was already a velocity squared, no need to square again

- Froude loss term was not properly initialized

- add missing halo updates for internal tide speed

- compute residual/critical slopes loss only where it has a meaning,
  allows to clean up noise in field

- uh/vh in energy flux routines do not need to be inout

- missing unit scaling for frequency