In order to use a custom partition layout in the partition module, we
need to write this layout in the module's config file, and store it into
a dedicated object.
As it doesn't look appropriate to extend an existing class with layout
information, we create a new PartitionLayout class, which will be used
to parse the layout from the config file and keep it in memory.
Signed-off-by: Arnaud Ferraris <arnaud.ferraris@collabora.com>
