Restore apply button for color table

The color table is only applied when the button is clicked. This will
hopefully prevent misleading the user into believing that the look-up table
is already applied to the node.
Throughout the code, it is implied that if we have a volume node, it has
a display node associated.

See Issue #13882
Add Transform module

The transform module can change the data from RAS to/from IJK.
This helps to get rid of the differences between ITK and VTK.

See Issue #13882
Improve Model Maker

Automatically set the skin's opacity to 0.2.
Add a toggle button for the skin's visibility.

See Issue #13882
Very simple workflow

Add a simple worflow option

See Issue #13882
Change workflow interface

Using accessible name to store the page's title and the accessible
description to store the help.
Add help collapsible groupbox. It has a label automatically filed with
the accessible descritption field.
Adding page number to the title and the next/previous buttons.
Hiding the first/last buttons.
Reformat the tranform module to just a button

See Issue #13882
Apply buttons tweaking

Change the buttons size and run CLI on pressed() signal so the button
will still be "pressed" while the cli is running.

See Issue #13882
Add rename to output comboboxes

See Issue #13882
Drastically improve the node color change performance

The volume node is observe by the setupMergeLabel() function that is
called upon the ModifiedEvent. Without the StartModify() and EndModify(),
each time the node was modified the function was called, slowing down the
process a lot.
Now the modified event is only called one at the EndModify().

See Issue #13882
Uniform GUI

Use same casing for the labels throughout the module, following the slicer
convention.
Also Using "WordWrap" in the help label.
Finally, moving the GoTo buttons next to the apply buttons.

See Issue #13882
Delete First/Last workflow buttons

There were not used anyway. Also leaving an empty space for the
next/previous button when at the last/first page.

See Issue #13882
GUI Tweaks

Add a), b) c) to collapsible groupbox titles.
Make the pose body output combo box visible in advanced mode.

See Issue #13882
Use Grayscale Model Maker for skin surface

The best way to have a skin surface is to use the grayscale model maker
and extract the skin from the difference between the body and the outside
(air). This prevent from having any hole in the surface from missing or
"thin" labels, especially when working whit down-sampled labelmaps.

See Issue #13882
Upon swtich to armature center view and switch to 3D only

See Issue #13882
Merge branch '13882-ImprovingWorkflow-JA' into workflow

* 13882-ImprovingWorkflow-JA:
  Upon swtich to armature center view and switch to 3D only
  Use Grayscale Model Maker for skin surface
  GUI Tweaks
  Delete First/Last workflow buttons
  Uniform GUI
  Drastically improve the node color change performance
  Add rename to output comboboxes
  Apply buttons tweaking
  Reformat the tranform module to just a button
  Change workflow interface
  Very simple workflow
  Improve Model Maker
  Add Transform module
  Restore apply button for color table