DOC: Updated processing of list styles.

* Preparing a text style based on the lists related information for the bullet/number,
which overrides text-properties applied to the list-item text (by either the text style
or the paragraph style). That one is referenced from the corresponding <text:list-level-style-*>
element.

NOTE: OOo lacks support for such approach, they store the info into the <style:text-properties>
child element of the <text:list-level-style-*> element.

* Providing proper value for the text:list-tab-stop-position attribute of the <style:list-level-label-alignment>
element. TODO: There might be problems on complex test files (nested list, etc.).
NOTE: Added a number of test into kofficetests.

----

TODO: Several level inheritance of font-size from some of the built-in paragraph styles (styles.xml)
is not working properly for the bullet/number of lists items in the layout. For text of the list item
it's working fine. Have to discuss that on #calligra.

TODO: Positioning of list items is not working properly in the layout.

Both TODOs can be tested with attachments to