For some control parts we need to provide the size or redefine
the size. Previously this was hardcoded, but this adds new
attriburtes for widget part definition:
- width, height: defines size for buttons in spinbox, the size of
  the checkbox or radiobutton
- margin-width, margin-height: increases the size (margin) of
  tab items by the specified amount

Change-Id: Ieea69b92ad21adc4f4954e7555f4d59348f5dea8
Reviewed-on: https://gerrit.libreoffice.org/68829
Tested-by: Jenkins
Reviewed-by: Tomaž Vajngerl <quikee@gmail.com>