CSS class for tables in the stylesheet for better readability

The Ubuntu wiki stylesheet should have a CSS class which could be added to any table from the wikimarkup, when you want a table with borders. Alternative row coloring would also work. Currently this must be done manually per-cell (or per-row).

For examples of tables in the wiki that would benefit from this change, see the following pages:
1) https://wiki.ubuntu.com/Lubuntu#Lubuntu_vs_Windows_7 (the desired looks is achieved here manually, which makes the wikimarkup cluttered)
2) https://wiki.ubuntu.com/UbuntuStudio/Documentation#ubuntustudio.org (here we have the unstyled table - which is just small enough to not be too hard to read with no alternating row bg colors)
3) https://wiki.ubuntu.com/Releases (while this is manually colored, here we can see a table which legibility takes a hit because there is no alternating row bg colors)
4) And more, each unstyled table would benefit from this immediately - without any change to the wikimarkup.