Distribution EOLE

We need an infrastructure to manage logical volumes in GenConfig

This infrastructure must works on all EOLE modules without problem
even if they don't provide the logical volume liste.

We need 3 things:

- some variables to store informations
- some utilities to get logical volume names on disk and check if we
can automatically extend volumes
- manage the automatic vs. non automatic cases in partition resize

• dicos/00_partitioning.xml: add 4 variables to store the per EOLE
  module name and percent extension of logical volumes and the list of
  created logical volumes.
  Fill the list of logical volume names with existing ones.
  Fill the extension percent with “0” for every logical volume, the
  pretemplate will have a special case.

• pretemplate/00-partitioning: do not use the same sizing variable
  between automatic extension of standard partitioning and manual size
  definition.
  (extend_lv): better message for logical volume with “0%” extension.

Ref: #21486